Math Help - help

1. help

plz solve it

2. First two questions are not well typed. It should be $dy\,dx.$

Now, to make polar transform, draw the region you're integrating.

The first integral in polar coordinates is $\int_0^{2\pi } {\int_0^1 {r\,dr\,d\theta } } .$ (I dunno if this is the integral, but its result agrees with the double integral in cartesian coordinates.)

3. The second question is equal to the first one.

We have a full circle. This in polar coordinates

$\int_0^{2\pi } {\int_0^a {r\,dr\,d\theta } } .$

Or by reversing integration order. (Fubini-type Theorem.)

4. Thanks

Thank You Krizalid.