Hi I'm having trouble with integration, can someone please help me integrate this: $\displaystyle \int_0^\infty e^{-\frac{x}{y}} dx $
Follow Math Help Forum on Facebook and Google+
Originally Posted by Pengu Hi I'm having trouble with integration, can someone please help me integrate this: $\displaystyle \int_0^\infty e^{-\frac{x}{y}} dx $ It's an improper integral so the first step is: $\displaystyle \lim_{\alpha \rightarrow + \infty} \int_0^\alpha e^{-\frac{x}{y}} dx $. If you need more help please show all your working and say where you're stuck.
1. Integral of $\displaystyle e^{-x/y}$ function is $\displaystyle -y*e^{-x/y} + C$. 2. $\displaystyle -y*e^{-x/y} -> 0$ when $\displaystyle x -> +inf$ Then the answer is $\displaystyle y$
Originally Posted by ialbrekht 1. Integral of $\displaystyle e^{-x/y}$ function is $\displaystyle -y*e^{-x/y} + C$. 2. $\displaystyle -y*e^{-x/y} -> 0$ when $\displaystyle x -> +inf$ Then the answer is $\displaystyle y$ Not clear enough (or may-be just wrong) , what happens if y<0?? Also what happens when y>0?? CB
i was about to say that but i forgot. calculations are valid for positive values. (The integrand is a positive function, it's impossible to get a negative number.)
View Tag Cloud