If 3cot²x - 7cosec² x + 7 = 0, then the value of x (0 ≤ x ≤ 90º) is:

If 3cot²x - 7cosec² x + 7 = 0, then the value of x (0 ≤ x…

If 3cot²x - 7cosec² x + 7 = 0, then the value of x (0 $\leq$ x $\leq$ 90º) is:

Show answer & explanation

Correct answer: C

Explanation

The correct answer is option 3 i.e. 90º.

3cot²x - 7cosec²x + 7 = 0

⇒ 3cot²x - 7 (1 + cot²x) + 7 = 0

⇒ 3cot²x - 7 - 7 cot²x + 7 = 0

⇒ -4 cot²x + 0 = 0

⇒ 4 cot²x = 0

⇒ Cot x = 0

⇒ x = 90° (since cot x = 0 at x = 90°)