# Converting from exponential to polar form

• May 2nd 2013, 10:09 PM
Brennox
Converting from exponential to polar form
I would really appreciate some help/working on this. please view attached or view the link.

http://i.imgur.com/LraAmqE.png
• May 2nd 2013, 10:55 PM
chiro
Re: Converting from exponential to polar form
Hey Brennox.

Recall that r^2 = x^2 + u^2 and theta = arctan(y/x).

With the limits you need to basically look at lower and upper limits of x and y and substitute the values of theta and r given those limits.

When y = 0 what does r equal? What about when y = SQRT(36 - x^2)?

It might help you to first draw your original region of integration on some paper and then use this to derive your region in terms of polar co-ordinates.

If you have a circular region, then r is constant. If it changes, then see how it changes with regards to the angle theta.

Also remember that in multivariable substitutions, you need to calculate the Jacobian.
• May 2nd 2013, 11:03 PM
Brennox
Re: Converting from exponential to polar form
oh thanks, does e^(x^2+y^2) translate into re^r^2?
• May 2nd 2013, 11:05 PM
Brennox
Re: Converting from exponential to polar form
ermmm when y = SQRT(36-x^2), r or 'A' = 6?
• May 3rd 2013, 03:23 AM
chiro
Re: Converting from exponential to polar form
Yeah it should be e^(r^2)*r if you factor in the Jacobian.