hey guys help me :D

wuts the integral of $$e ^{-x ^{2}}$$?

Question

hey guys help me :D

wuts the integral of $$e ^{-x ^{2}}$$?

anonymous · Answer

i got $$e ^{-x ^{2}}(-2x)$$ but i don't think that's right...

anonymous · Answer

No, it requires the error function. It is $\frac 1 2 \pi^{1/2} erf(x)$.

anonymous · Answer

wait wuts the error function? and how come the integration rules don't apply here????

anonymous · Answer

http://www.youtube.com/watch?v=FYNHt4AMxc0

anonymous · Answer

lol can't go on youtube right now :P

anonymous · Answer

doesn't it significantly change the integral value?

anonymous · Answer

Yes. It's essentially $\sqrt \pi$.

anonymous · Answer

ok so lemme tell u the whole problem. im trying to find the area under the curve in the interval (0,0.922) for the function i posted, and im getting a negative value...the sq rt pi won't change the sign...the graph is above the x-axis so im suppose to get a positive value...

anonymous · Answer

http://www.wolframalpha.com/input/?i=1%2F2*sqrt%28pi%29*erf%28.922%29+-+1%2F2*sqrt%28pi%29*erf%280%29

anonymous · Answer

It's positive.

anonymous · Answer

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