U-Substitution in Calculus: Solving a Difficult Integration Problem

[javacola]

Homework Statement

1~~0 (x^7)/sqrt(4-3x^16) dx

The Attempt at a Solution

There really isn't one. I am as clueless as one can get in calculus. I know that I am supposed to substitute the variable "u" in for a section of this problem, but really don't know anything after that. I understand derivatives but that is about it. If someone could walk me through this problem it'd be great.

 

[LCKurtz]

Homework Statement

1~~0 (x^7)/sqrt(4-3x^16) dx

The Attempt at a Solution

There really isn't one. I am as clueless as one can get in calculus. I know that I am supposed to substitute the variable "u" in for a section of this problem, but really don't know anything after that. I understand derivatives but that is about it. If someone could walk me through this problem it'd be great.

You know that when you make a u substitution, you need the du to be in the integral. You have x⁷ sitting there. What u might give you an x⁷ in the du? Think about that.

 

[javacola]

You know that when you make a u substitution, you need the du to be in the integral. You have x⁷ sitting there. What u might give you an x⁷ in the du? Think about that.

7x^6?

 

[LCKurtz]

You know that when you make a u substitution, you need the du to be in the integral. You have x⁷ sitting there. What u might give you an x⁷ in the du? Think about that.

7x^6?

No, you are just guessing. If you want to get x⁷ in the answer for du, what must u be? You got x⁶ in your answer, not x⁷. C'mon, you can do better than that.

 

[javacola]

No, you are just guessing. If you want to get x⁷ in the answer for du, what must u be? You got x⁶ in your answer, not x⁷. C'mon, you can do better than that.

I told you I don't know much about calculus...so just saying "come on" isn't going to magically help me get the answer.

Is u x^7? Or 4-3x^16?

 

[HallsofIvy]

If you honestly have no idea what to do, even with LCKurtz's very good hint, there isn't a lot we can do for you. You really need to talk to your teacher about this kind of problem.