Question

 

Evaluate

`(sin ^2 63^@ + sin^2 27^@)/(cos^2 17^@+cos^2 73^@)`

 

Answer 1

 

`(sin ^2 63^@ + sin^2 27^@)/(cos^2 17^@+cos^@73^@)`

`(= [sin(90^@ - 27^@)]^2+sin^2 27^@)/([cos(90^@ - 73^@)]^2 + cos^2 73^@)`

`= ([cos27^@]^2 + sin^2 27^@)/([sin 73^@]^2 + cos^2 73^@)`

`= (cos^2 27^@ + sin^2 27^@)/(sin^2 73^@+ cos^2 73^@)`

= 1/1 (As sin²A + cos²A = 1)

= 1