1)

If tan θ = √n for some non-square natural number n, then sec 2θ is :


A) a rational number

B) an irrational number

C) a positive number

D) none of the above

Answer:

Option A

Explanation:

$\cos2\theta =\frac{1-\tan^{2}\theta}{1+\tan^{2}\theta}$

= $\frac{1-n}{1+n}$→ $\sec2\theta =\frac{1+n}{1-n}$

Since, n is non - square natural number, n ≠ 1

.'. $\sec2\theta =\frac{1+n}{1-n}$ = rational number