Math Is Fun Forum

Daniel123

Member

Registered: 2007-05-23

Posts: 663

Integration

Sorry about that last post to whoever deleted it, I typed something extremely stupid and had to remove it quickly

Does anyone mind checking if this is correct?

Substituting x = sin2θ,

EDIT: I realise now that it would have been better to change the limits of the integral and not had to use arcsin etc. It's just that I have never changed the limits before, so it didn't cross my mind.

Thanks.

Last edited by Daniel123 (2008-03-14 10:25:13)

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Integration

Don't worry about your previous post, I just thought that you must have figured out how to answer your own question after you'd posted it and that the forum wasn't letting you delete posts. It sometimes does that.

As for this question, as far as I can tell everything is perfect, although as you said, you can make life a bit easier by changing the limits of integration instead of going back to x.

Doing that and a few other things gives the integral as

, which is much nicer to evaluate without a calculator.

---

Why did the vector cross the road?
It wanted to be normal.

Daniel123

Member

Registered: 2007-05-23

Posts: 663

Re: Integration

It was a non-calculator question.. so no it wasn't nice to do without one. Next time I will definitely change the limits.

Thanks.