Question

If sin square theta = 0.75, then cos =

Answer 1

Answer:

$\cos\theta=\pm0.5$

Step-by-step explanation:

Given:

$\sin^2\theta=0.75$

To find $\cos\theta$

Using trigonometric relations for sums and differences of squares of the ratios.

We know:

$\sin^2\theta+\cos^2\theta =1$

Plugging in  $\sin^2\theta=0.75$ in the above relation.

$0.75+\cos^2\theta =1$

Subtracting both sides by 0.75.

$0.75+\cos^2\theta-0.75 =1-0.75$

$\cos^2\theta =0.25$

Taking square root both sides.

$\sqrt{\cos^2\theta} =\sqrt{0.25}$

∴ $\cos\theta=\pm0.5$  (Answer)