Let I=∫6π3πlog(tanx)dx
Using the King Property of definite integrals:
∫abf(x)dx=∫abf(a+b−x)dx
Here, a=6π and b=3π, so:
a+b=6π+3π
=6π+62π
=2π
Therefore:
I=∫6π3πlog(tan(2π−x))dx
Using the complementary angle formula tan(2π−x)=cot(x)=tanx1:
I=∫6π3πlog(tanx1)dx
Using the logarithm property log(a1)=−log(a):
I=∫6π3π−log(tanx)dx
I=−∫6π3πlog(tanx)dx
I=−I
I=−I
I+I=0
2I=0
I=0
Therefore, the value of the integral is 0.