Find cos π / 5 times Cos2 π / 5 times cos3 π / 5 times Cos4 π / 5

Find cos π / 5 times Cos2 π / 5 times cos3 π / 5 times Cos4 π / 5

Multiply by sin π / 5 and divide by sin π / 5
The original formula is sin π / 5 times cos π / 5 times Cos2 π / 5 times cos3 π / 5 times Cos4 π / 5 divided by sin π / 5
=0.5 times sin2 π / 5 times Cos2 π / 5 times cos3 π / 5 times Cos4 π / 5 divided by sin π / 5
=0.25 times SiN4 π / 5 times cos3 π / 5 times Cos4 π / 5 divided by sin π / 5
=0.125 times sin8 π / 5 times cos3 π / 5 divided by sin π / 5
=- 0.125 times SIN3 π / 5 times cos3 π / 5 divided by sin π / 5
=-(1 / 16) multiplied by sin6 π / 5 divided by sin π / 5
= 1/16