How do you express sin(pi/ 8 ) * cos(( ( 7 pi) / 4 ) sin(π8)cos((7π4) without using products of trigonometric functions?

1 Answer
Mar 20, 2016

P = (sqrt2/2)sin (pi/8)P=(22)sin(π8)

Explanation:

P = sin (pi/8)cos ((7pi)/4)P=sin(π8)cos(7π4)
cos ((7pi)/4) = cos (-pi/4 + 2pi)= cos (-pi/4) = cos pi/4 = sqrt2/2cos(7π4)=cos(π4+2π)=cos(π4)=cosπ4=22
P can be expressed as:
P = (sqrt2/2)sin (pi/8)P=(22)sin(π8)
We can find P by evaluating #sin (pi/8), if being asked.