Integral + Brainfart | Solve Integral Problem

[James889]

Hai,

I have the following Integral i can't get right:
\int_{-8}^8\frac{(6e^{4x}-2)^2}{e^{4x}}

After i squared the bracket i end up with~~\frac{36e^{8x}-24e^{8x}+4}{e^{4x}}

So, after dividing thru by e^{4x} i have:

36e^{4x}-24e^{4x}+\frac{4}{e^{4x}}

Integrating gives:
9e^{4x} - 6e^{4x} +4~ln(e^{4x})

I must be doing something wrong because i end up with the wrong answer =/
But what?

 

[zcd]

\int 36e^{4x}-24e^{4x}+\frac{4}{e^{4x}}\,dx=\int 36e^{4x}-24e^{4x}+4e^{-4x}}\,dx
You skipped the u substitution for the last term.

 

[rl.bhat]

The third integration becomes
Int(4*e^-4x) = - e^-4x.

 

[Pengwuino]

The second term in line 2 should be - 24e^{4x}. Also, the integral of 4e^{ - 4x} is not 4\ln (e^{4x} )