Which of the following statement is correct?
I. If , then
II. The value of is

Question

Question

This question was previously asked in

SSC CGL 2022 Tier-I Official Paper (Held On : 07 Dec 2022 Shift 4)

Answer 1

Given:

k + 1/k = 12

Formula used:

(x + 1/x)2 = (x2 + 1/x2) + 2

(a - b)(a + b) = a² - b²

Calculation:

Take first statement

k + 1/k = 12

using

(x + 1/x)2 = (x2 + 1/x2) + 2

(k2 + 1/k2) = 144 - 2

(k2 + 1/k2) = =142

So, the first statement is true.

Take second statement

Using (a - b)(a + b) = a2 - b²

So, the second statement is not true.

Therefore only statement I is true.

∴ Option 1 is the correct answer.

Mistake Points

Please note that,

(K⁴)² = K^{4 * 2} = K⁸

So statement 2 is not correct.