Question

sin^2(3pi/8)+sin^2(pi/8)

Answer 1

we know ,
sin^2@ + cos^2 @ = 1
now ,
sin^2 (3pi/8) +sin^2 (pi/8)

=> sin^2 (3pi/8) +{sin (pi/2 -3pi/8)}^2

=> sin^2 (3pi/8) + {cos(3pi/8)}^2

=> sin^2(3pi/8) + cos^2 (3pi/8)

=> let. (3pi/8) =@
then ,
sin^2@ + cos^2@ = 1 by above formula