AP Polycet (Polytechnic) 2021 Previous Question Paper with Answers And Model Papers With Complete Analysis

26) If log2 x2 = 2, then x=

A) 2
B) -2
C) 3
D) -3

View Answer
A) 2

Explanation:To solve the equation \log_2 x^2 = 2, let’s follow these steps:
Step 1: Rewrite the Logarithmic Equation in Exponential Form
Given:
\log_2 x^2 = 2
This means:
2^2 = x^2
4 = x^2
Step 2: Solve for x
Take the square root of both sides:
x = \sqrt{4} \quad \text{or} \quad x = -\sqrt{4}
x = 2 \quad \text{or} \quad x = -2
Step 3: Verify the Solutions
Both x = 2 and x = -2 satisfy the original equation because:
\log_2 (2)^2 = \log_2 4 = 2 \quad \text{and} \quad \log_2 (-2)^2 = \log_2 4 = 2
Final Answer
Both A. 2 and B. -2 are correct solutions. However, if the question expects a single answer, either 2 or -2 is acceptable.
If the options are to be interpreted as allowing multiple correct answers, both A and B are correct.
But typically, such questions expect one correct choice, so you can select either A. 2 or B. -2 based on the context.
However, looking at the options, both A and B are correct. If only one option is to be selected, the primary answer is: A. 2
(and B. -2 is also correct)
If the question implies selecting all correct options, then both A and B are correct.
But in most standard cases, the simplest answer is:
A. 2
*(Note: Since logarithms of squared numbers are defined for both positive and negative values, both solutions are valid.)
Conclusion
The correct options are A and B, but if only one answer is expected, A. 2 is the standard choice.
Final Answer: A. 2 (and B. -2 is also correct)

27) Set of even prime numbers is

A) {3,4}
B) {4,6,8}
C) {8,10}
D) {2}

View Answer
D) {2}

28) If A∩B = B, then the correct statement is

A) A⊆B
B) B⊂A
C) A≠Φ
D) B≠Φ

View Answer
B) B⊂A

Explanation:We are given:
A ∩ B = B
This means:
All elements of B are also in A, because the intersection gives back B itself.
So, B is a subset of A, i.e.,B ⊆ A
Which matches Option B: B ⊂ A
(Note: In some contexts, ⊂ is used to mean ⊆ — subset. If strict subset is intended, the wording would be different.)
Final Answer: B ⊂ A

29) Which of the following sets are finite

A) set of all natural numbers
B) set of all prime numbers
C) set of months in a year
D) none of these

View Answer
C) set of months in a year

30) The number of zeroes, a biquadratic polynomial can have at most is

A) 1
B) 2
C) 3
D) 4

View Answer
D) 4

Explanation:A biquadratic polynomial is a polynomial of degree 4, typically of the form:
ax^4 + bx^2 + c
Even though it’s written in terms of x^2, its highest power is 4.
Shortcut:
A polynomial of degree n can have at most n real or complex zeroes.
So, a biquadratic polynomial (degree 4) can have:
At most 4 zeroes
Final Answer: 4

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