## hba 2 years ago A trick for you guys,maybe you know it but i just want to share it.

1. hba

Let me show you a trick differentiate $e ^{x}sinx$ the differential would be $e^x(sinx+cosx)$ You just take the e^x out of the bracket and then write sinx and then diffrentiate it and write what comes. Let me show you another example differentiate $e^x tanx$ the differential would be $e^x(tanx+\sec^2x)$ In this case you also leave the e^x and then write tanx in the bracket and then diffrentiate it and you get sec^2x Let us form a general formula out of it. $e^x x$ so to diffrentiate it $e^x(x+\frac{ d(x) }{ dx })$

2. hartnn

$$[e^xf(x)]'=e^x(f(x)+f'(x))$$ works only for e^x, not for $$e^{ax}$$.

3. hba

Yeah.

4. hartnn

$$[e^{ax}f(x)]'=e^x(af(x)+f'(x))$$

5. ethompsonn

to much smart ppl, must go dumb down..

6. UnkleRhaukus

nice

7. DLS

that is the original way how i do it lol :D

8. hba

Well i was taught this as a trick lol :D