DSSSB TGT Computer Science PYQ (Technical), 7 Aug 2021, Shift 3

Explanation

u = sin⁻¹(f), where f = (x + 2y)/(x⁸ + y⁸) is homogeneous of degree 1 − 8 = −7. By the corollary of Euler's theorem, x(∂u/∂x) + y(∂u/∂y) = n·f(u)/f'(u) = −7 sin u/cos u = −7 tan u.

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A proposal tries to persuade the reader to act and highlights the benefits of the proposed idea. Both functions are at play.

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Ctrl + Z undoes the last action in MS Word. Ctrl + J justifies, Ctrl + I is italic and Ctrl + K inserts a hyperlink.

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A joystick sends user input to the computer. Plotters, printers and speakers are output devices.

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Functions (which return a value) and subroutines (procedures) are both types of subprograms.

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Memory management keeps track of which parts of memory are in use and which are free, and it allocates free space to the processes to be loaded next. Both are primary tasks.

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The unary * operator, which gives the value a pointer points to, is called the indirection (dereference) operator.

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Pass 1 moves 85 to the end: 37, 21, 54, 68, 12, 9, 57, 85. Pass 2 moves 68 to its place: 21, 37, 54, 12, 9, 57, 68, 85.

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The comma operator evaluates v = 20, then v + 2, and returns the last value, so k = 22. (The "/n" is printed literally after it.)

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22→4, 28→1, 23→5, 12→3. 13 mod 9 = 4 is taken, so linear probing tries 5 (taken), then 6, which is free. So 13 goes to index 6.

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Batch files on DOS/Windows use the .BAT extension (newer ones may also use .CMD).

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Real-time operating systems are either hard (deadlines must always be met) or soft (occasional misses are tolerated). Both are types.

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A base-b system uses b symbols, from 0 to b − 1 (e.g. decimal uses 0-9 and binary uses 0-1).

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With n bits there are 2ⁿ combinations, which cover 0 to 2ⁿ − 1, so n bits are enough.

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The collating sequence is the defined order of the characters in a character set (e.g. ASCII), used when comparing and sorting text.

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The output is 0 only when all inputs are 1 and 1 otherwise, which is (ABC)', the NAND function.

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An astable multivibrator has no stable state; it keeps switching between its two quasi-stable states, which is how it works as an oscillator.

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The figure of merit of a logic IC is the speed-power product: propagation delay × power dissipation. A lower value is better.

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A T flip-flop toggles its state on each clock pulse when T = 1 and keeps its state when T = 0. Both statements are correct.

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XNOR is the equivalence function, written Y = A ⊙ B. A ⊕ B is XOR, (A + B)' is NOR and (AB)' is NAND.

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The hierarchical model (e.g. IBM's IMS, 1960s) is the oldest of these. The relational model came in 1970, and the object-oriented and deductive models later.

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DDLC is the Database Development Life Cycle: the stages of planning, designing, building and maintaining a database.

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In X → Y, X is the determinant and Y is the dependent, because X determines the value of Y.

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Connection traps (fan traps and chasm traps) are problems that can arise in an ER model, where the relationships do not give the intended paths between entities.

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A multivalued attribute is drawn as a double oval. A double diamond is an identifying relationship and a double rectangle is a weak entity.

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A checkpoint is a point where all log records and modified buffers are written to disk, which synchronises the database with the log and limits how much must be redone during recovery.

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2K = 2048 = 2¹¹ words, so 11 address lines are needed, and each word is 16 bits, so 16 data lines.

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An n-bit parallel (ripple-carry) adder chains n full adders, one per bit.

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XOR gates on the B inputs pass B through when the control is 0 and invert it when the control is 1. With carry-in = 1, this gives 2's complement subtraction, so one circuit does both.

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A + B = 01110110 (118) + 10000101 (133) = 11111011 (251), and B + 1 = 10000101 + 1 = 10000110.

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Pseudo-instructions (assembler directives such as ORG, END, DEC) are commands to the assembler. They are not translated into machine instructions.

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font-weight sets how bold the text is (normal, bold, 100-900). font-style sets italic.

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list-style is the shorthand property that sets list-style-type, list-style-position and list-style-image in one declaration.

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Under accounting rules, a decrease in an asset is credited and an increase in a liability is credited. Both are correct.

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Depreciation is the decline in the book value of fixed assets, and it continues throughout the asset's useful life. Both are features.

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Using the forward difference approximation, f'(3) ≈ [f(4) − f(3)]/h = (0.602 − 0.477)/1 = 0.125.

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ROCOF stands for Rate of Occurrence of Failure, the frequency of failures over time, used as a software reliability metric.

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In a DFD, a rectangle is an external entity, two parallel lines are a data store, the document shape is output, and a circle (bubble) is a process.

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Structured partitioning divides a program both horizontally (separate branches for major functions) and vertically (control at the top, work done at the bottom).

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A level-0 DFD is called the context diagram: it shows the whole system as one process with its external entities.

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Coupling measures the degree of functional interdependence between two modules. Low coupling is desirable. Functional strength within one module is cohesion.

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A code walkthrough is an informal technique for analysing code, so I is true. It is done after the module has been coded and compiled, not before coding, so II is false.

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Boundary value analysis tests values just outside and at each boundary of the valid range 1-4000: 0, 1, 4000 and 4001.

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javap is the Java class file disassembler. It shows the fields, methods and bytecode of a .class file. javac compiles and javadoc generates HTML docs.

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In Java, a final class cannot be subclassed and a final method cannot be overridden. Both are correct.

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With a String on the left, each + is string concatenation: "exam" + 9 gives "exam9", and so on, giving "exam999". The 9s are not added to 27.

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With RR (q = 1), the order is a, b, c, d, a, c, d, a, c, a. b ends at 2 and d at 7, and a's fourth slice ends at time 10.

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First-generation computers were programmed in machine language (and some assembly). High-level languages came with later generations.

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RTP (Real-time Transport Protocol) carries real-time audio and video over IP networks.

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The File Allocation Table (FAT) keeps entries for the files on a disk, recording which clusters each file occupies.

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A disk surface is divided into tracks, tracks into sectors, and the same tracks across all platters form a cylinder.

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Both statements are wrong. Parallel processing (shared memory) is tightly coupled, and distributed systems are loosely coupled.

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An inferior good is one whose demand falls as income rises (consumers switch to better goods). Demand for a normal good rises with income.

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When RBI sells bonds (open market operation), buyers pay with money that leaves the banking system. This reduces bank reserves and so the money supply.

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Tripled inputs giving tripled output is constant returns (I wrong), doubled output is decreasing returns (II wrong), and more than tripled output is increasing returns (III correct).

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FTP is file transfer, TFTP is trivial file transfer, Telnet is remote login, and UDP sends datagrams.

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Infrared waves travel through air with no physical conductor, so they are unguided media. Fiber optic, twisted pair and coaxial cable are guided.

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DHCP assigns IP addresses automatically from a pool and also allows manual (static) assignment, along with other network settings.

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A VPN (Virtual Private Network) creates encrypted tunnels over a public network such as the internet, linking remote users or sites privately.

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In peer-to-peer networks every peer can share and access data on other peers directly. No dedicated server is needed, so II is false.

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Compiling Intermediate Language to native machine code just before it runs is Just-In-Time (JIT) compilation. First-In-Time compiling does not exist.

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/etc holds system-wide configuration files (e.g. /etc/passwd, /etc/fstab). Home directories are in /home.

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Smart cards, e-wallets and electronic funds transfer are all types of electronic payment systems.

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As keyed: stateful inspection firewalls track inbound network traffic, packet filters are built into operating systems/routers, proxy servers front services such as mail servers, and application-level gateways handle services like Telnet.

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An in-order traversal (Left, Node, Right) of a BST visits the keys in ascending order. Pre-order and post-order do not.

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LR and RL cases each need two single rotations, so they are called double rotations. LL and RR need only one.

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Bottom-up heapify: 215 swaps with 300, 250 swaps with 300, then 289 swaps with 300. No other node violates the heap, so 3 interchanges.

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Pass 1 (units): 720, 355, 436, 457, 657, 329, 839. Pass 2 (tens, stable): 720, 329, 436, 839, 355, 457, 657.

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Pass 1 swaps A with H: A, V, H, T, L, N, K. Pass 2 swaps H with V: A, H, V, T, L, N, K. Pass 3 swaps K with V: A, H, K, T, L, N, V.

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An office automation system supports office work such as word processing, email and scheduling. Annual budgeting is a management planning task.

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IRCTC reservations, electronic banking through payment gateways and logistics management applications are all information systems that support management. All three are examples.

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GPRS gives end-to-end packet-switched data transfer for both point-to-point and point-to-multipoint services.

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An LCD does not emit light; it modulates light from a backlight, so it is non-emissive. Plasma, thin-film electroluminescent and LED displays are emissive.

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RGB = 1 − CMY: (1 − 0.25, 1 − 0.65, 1 − 0) = (0.75, 0.35, 1).

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Cohen-Sutherland code (TBRL): P(−4, 2) has x < −3, so it is left: 0001. Q(−1, 8) has y > 6, so it is above: 1000.

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A wireframe is a rough skeletal outline of a website's layout made before the actual design and development.

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A URL has a protocol (https://), a hostname (www.example.com) and a path made of the directory and filename. All three are parts.

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Tacit knowledge is personal, based on experience and hard to formalise or put into words. Explicit knowledge can be written down and shared.

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An experiment report includes the aim, the apparatus used, the procedure, the observations and the results, so both are included.

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Big-Omega (Ω) gives an asymptotic lower bound. Big-O gives an upper bound and Theta (θ) a tight bound.

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A diamond with Yes and No branches leading to different actions is the decision (selection, if-else) structure.

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A flowchart is a pictorial representation of a program's logic. Pseudo code and algorithms are written in text.

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The probabilities must add to 1: 9K + 10K² = 1, so 10K² + 9K − 1 = 0, i.e. (10K − 1)(K + 1) = 0. Since K > 0, K = 1/10.

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With replacement the draws are independent: P = (8/18) × (8/18) = (4/9)² = 16/81.

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In a learner-centred approach, students learn through peer interaction and get chances to question, explore and experiment. Both are characteristics.

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Television gives both sound and pictures, so it is an audio-visual aid, not only a visual aid. The other pairs are correct.

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Peer assessment helps students consolidate learning through dialogue with peers, and it teaches them to give and receive constructive feedback based on clear criteria. Both apply.

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Standardization ensures that the items are designed to measure a clearly defined domain, and that administering, scoring and interpreting follow a uniform procedure. Both are ensured.

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Children's motivation, self-confidence and curiosity toward a language all play an important role in acquiring it.

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A metaphor calls one thing another without "like" or "as". "The camel is the ship of the desert" is a metaphor; statement I is a plain fact.

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Dictionaries are informative literature, and novels are creative or imaginative literature. Both pairs are correct.

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Theatre, music and puppetry are all performing arts, since they are presented live before an audience.

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Sex ratio, education and health are all indicators of the status of women and gender.

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Formal and non-formal education aim to improve the quality of life and living standards, and to empower girls through values, attitudes and life skills. Both are objectives.