Evaluate

[CatchThis2]

[x^3 sqrt (2+x^4)] dx

I made u=2+x^4
du=4x^3

From there I got 1/3 du= x^4 dx

I got a final answer of 2/9 (2+x^4)^3/2 ?

 

[Deleted member 4993]

x^3 sqrt 2+x^4 dx

I made u=2+x^4 <<< Why?

du=4x^3 dx

From there I got

1/3 du= x^4 dx <<< How - this is incorrect

I got a final answer of 2/9 (2+x^4)^3/2 ?

Is your problem:

\(\displaystyle \int \left [x^3\cdot \sqrt{2+x^4}\right] dx \ = \ ???\)

If yes - then you you should have written:

Evaluate

Integral[x^3 sqrt (2+x^4)] dx

Without the grouping symbols the problem does not make sense.

Edit your post with the grouping symbols - then I can help you.

 

[CatchThis2]

The way you wrote the problem is correct.

 

[Deleted member 4993]

The way you wrote the problem is correct.

Then edit your post with grouping symbols - like I showed you.