algebra 2 high school

Question

For a given angle theta, sin theta=0.723. Use pythagorean identity to find two possible values for cos theta.

Answer 1

sin theta=0.723

 

sin θ= 0.723

 

cos ²θ=1-sin² θ 

      

          =1-(0.723)²

 

           =1-0.522729

 

           =0.477271

cos θ= ±0.690

 

cos θ=+0.690  and cos θ=-0.690