Given that sin x = 3/4
where x is an obtuse angle, find the exact value of cos x.

Solving a trigonometric equation, it is found that:

The sine and the cosine of an angle x are related by the following equation:

In this problem:

, thus:

Since the cosine is negative.

A similar problem is given at link

Step-by-step explanation:

sin x =3/4

x is an obtuse angle and sin x is positive .

∴ x lies in 2nd quadrant.

Hence cos x is negative.

step-by-step explanation:

try remembering the steps

this may not be at all, but i use the same website you're using for school, and if i'm stuck doing one of these i try to look for it on the section.