Question #9ae03

1 Answer
Feb 5, 2017

5/8(root5(y^4-8))^8+C.58(5y48)8+C..

Explanation:

We will use the Substitution : root5(y^4-8)=x:5y48=x.

rArr (y^4-8)=x^5 rArr d(y^4-8)=d(x^5), i.e., 4y^3dy=5x^4dx(y48)=x5d(y48)=d(x5),i.e.,4y3dy=5x4dx.

"Therefore, "I=int(root5(y^4-8))^3(4y^3dy)Therefore, I=(5y48)3(4y3dy)

=int(x^3)(5x^4)dx=5intx^7dx=5(x^(7+1)/(7+1))=5/8x^8=(x3)(5x4)dx=5x7dx=5(x7+17+1)=58x8.

rArr I=5/8(root5(y^4-8))^8+C.I=58(5y48)8+C..