If ∫x26(x−1)17(5x−3)dx=x27.(x−1)18k+c, where c is the constant of integration, then the value of k is
9
Differentiating both sides gives
x26.(x−1)17(5x−3)=1k[x27.18(x−1)17+(x−1)1827x26]
=x26(x−1)17k[18x+27(x−1)]
=x26(x−1)17k(45x−27)
=9x26(x−1)17k(5x−3)
⇒k=9