# Thread: Indefinite Intergral - 1 question - Please Help

1. ## Indefinite Intergral - 1 question - Please Help

$\displaystyle \int( \sqrt[3]{u} + \cos2u + e^{-u} )du$

e = Exponential

2. Originally Posted by ForgottenMemorie
$\displaystyle \int( \sqrt[3]{u} + \cos2u + e^{-u} )du$

e = Exponential
Some reminders:
$\displaystyle \int \sqrt[3]{u}~du = \int u^{1/3}~du$
Use the power rule for integration.

$\displaystyle \int cos(2u)~du$
Use the substitution x = 2u. Then you need to know
$\displaystyle \int cos(x)~dx = sin(x) + C$.
(This is not the answer. There's a multiplicative factor too.)

$\displaystyle \int e^u~du = e^u + C$
Let x = -u. Then you need to know
$\displaystyle \int e^x~dx = e^x + C$

-Dan

3. $\displaystyle \int u^{1/3} \sin2u e^{-x}$

It that the answer>?

4. That was not a new question, that was a typo, i was hving trouble typing what i wanted in.

5. Originally Posted by ForgottenMemorie
$\displaystyle \int u^{1/3} \sin2u e^{-x}$

It that the answer>?
How could that possibly be the answer? You are adding the terms in the integrand, so you wouldn't multiply. And I presume that your question is asking you to integrate, so do the integrals.

Or is the question actually to integrate
$\displaystyle \int u^{1/3}~sin(2u)~e^u~du$

-Dan