Question

Find cos x if sin^2x-1/cos x = -1 a. –1 b. 2 c. 1 d. 0

Answer 1

Answer:        1

Step-by-step explanation:

Alright, lets get started.

The given expression is :

$\frac{sin^2x-1}{cosx}=-1$

As per Pythagorean identity,

$sin^2x + cos^2 x = 1$

taking 1 to left side and $cos^2 x$ to right side

$sin^2 x-1=-cos^2x$

Now plugging the value of $sin^2 x-1$ in given expression

$\frac{-cos^2x}{cosx} =-1$

cosx will be cancelled, so

$-cosx=-1$

Multiplying -1 in both sides, it will equal to

$cos x= 1$    ........................ Answer (C)

Hope it will help :)