Solve Integration Problem With u-Substitution

[fran1942]

Hello, I am trying to integrate the following using "u-substitution", however I am not getting the correct result. Can someone please advise where I am going wrong.
The following is my attempt:

x(x-1)^3

u = x-1

du/dx = 1
du/1 = dx

x(u)^4 / 4

My final (incorrect) answer.
x(x-1)^4 / 4

 

[tiny-tim]

hello fran1942!

(try using the X² button just above the Reply box )

x(u)^4 / 4

no, you must substitute every x …

you can't end up with something that still has an x in it!​

 

[Shootertrex]

You should rewrite the equation. If you foil out the (x-1)³ to x³-3x²+3x-1 then multiply by the x to get x⁴-3x³+3x²-x I think you will have an easier time integrating and without using a u-sub.

 

[Biosyn]

Don't forget the constant of integration!

 

[ketty55555]

we cannot seem to integrate Plancks law to show that stefans boltzman constant is 5.67x10^-8