Let, I=π80∫2π(sinx)2023+(cosx)2023(cosx)2023dx ..... (1)
Using formula,
a∫bf(x)dx=a∫bf(a+b−x)dx
I=π80∫2π[sin(2π−x)]2023+[cos(2π−x)]2023[cos(2π−x)]2023dx
=π80∫2π(cosx)2023+(sinx)2023(sinx)2023dx ..... (2)
Adding equation (1) and (2), we get
2I=π80∫2π(sinx)2023+(cosx)203(sinx)2023+(cosx)2023dx
⇒2I=π80∫2πdx
⇒2I=π8[x]02π
⇒2I=π8×2π
⇒2I=4
⇒I=2