VIDEO: HOW TO SOLVE A DOUBLE INTEGRAL IN POLARS!

Here I bring you the video I told, I have had so much problems uploading but finally here it is!

MERRY CHRISTMAS!

Useful tips when integrating

As these days we´ve been reviewing integration, I think that is a good idea to bring to you some tips about integrating , that will help in order to not to make silly mistakes.

The first thing that is very recommendable is to sketch the region you are given. With a very simple sketch we will see much more clearly what the domain of the figure is and realize what we were asked for.

When we have this sketch, we get the bounds easily, so we write them as inequalities (<, >, ≤ and ≥), making sure that, at least, one of the variables has constant limits. And then we build up our integral, writing at the top and at the bottom the bounds previously calculated.

When you write this, note on the order you are integrating, because there is going to be almost always some variable with constant limits, and that variable therefore has to be the one on the outside integral.

It is recommendable also, to write the integration variable involved explicitly under each integral sign, this is to remind us which of x and y is considered a constant and which is considered a variable.

It is very helpful to learn by heart some easy formulas, to gain some precious time that will be very important in exams. (I will put here a link since I can´t write any math symbology here)

http://www.mathportal.org/calculus/integrals/integration-formulas.php

HOPE IT WAS HELPFUL AND SEE YOU IN THE NEXT POST THAT WILL BE A HOME-MADE VIDEO!