Answer:

Step-by-step explanation:
Problems like this require that you recognize that the denominator of the right term is a factor of the denominator of the left term. That is, you're supposed to know how to recognize and factor the difference of two squares.

Answer:

Step-by-step explanation:
The given cylindrical equation is

Multiply both sides by r.
.... (1)
The required formulas are

Substitute
in equation (1).


Add 1 on both sides.

![[\because (a-b)^2=a^2-2ab+b^2]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%28a-b%29%5E2%3Da%5E2-2ab%2Bb%5E2%5D)
It is the equation of a circle centered at (0,1) with radius 1.
Therefore, the equation in rectangular coordinates is
.
The student will have $135 in her bank account at the end of the ninth week. You can fine this out by finding out the amount she deposits a week and to do this you would take the $30 and divide it by 2 because she had $30 at the end of the second week.
30/2=15
So you see that the student deposits $15 each week, so to find out how much money she will have in 9 weeks you will multiply her $15 by 9.
15x9=135
So the student will have $135 at the end of the ninth week.