Question

Prove that sin 10° . sin50°. sin 70° = 1/8​

Answer 1

given given that sin 10° into sin50° into sin 17° is equal to 1 upon 8

now we multiply a pole and bottom side by 2/2

then we get 1/2 (2sin10°sin50°sin70°)

1/2sin10°{2sin70°sin50°}

we know that

2sinAsinB = cos (A-B) - COS(A+B)

then

=1/2sin10°(cos20°-cos120°)

on further the calculating we get

=1/2sin10°cos20°+1/4sin10°