Hello
How do you integrate this, Integral (5x/3)*e^-x/3
Thank you
Hm...
This is not the formula, but it looks like...
$\displaystyle \int_a^b f(x)g'(x) dx=\left[f(x)g(x)\right]_a^b - \int_a^b f'(x)g(x) dx$
And take $\displaystyle f(x)=5x/3$ and $\displaystyle g'(x)=e^{-x/3}$
Edit : your writing is confusing me... What is the original integral with f and g for you ?
Ok that's it
Set f(x)=e^-x/3
And g(x)=5x/3
Because g will be differentiated. Since the derivative of an exponential is in most case the same, it's not really useful to set g(x)=e^-x/3
Whereas if you differentiate a polynomial (5x/3), you will soon get to a constant.
Do you understand ?