Post Number Twelve

another week down, and i still suck at calculus.

This week went kind of like this. Study, Study, fail, fail, learn. Interesting right?

So Monday and Tuesday we reviewed stuff we didn't understand in order to be ready for the tests on wednesday and thursday. Turns out i still don't understand most of it.

First of all, i really can't grasp how to look at a graph and determine it's derivative and horizontal tangents and where it's concave up, down, etc. I need help with this bad, so please if who understands this well would like to i'd appreciate it.

Another thing I still can't seem to understand is optimization and angles of elevation. I don't know what my problem is but i just get lost in the problem before i even start it. I honestly think i'm just overwhelming myself and then not being able to work under the pressure i put myself under because most of the time i know what we're doing in class.

So after the tests we found out that as a whole we suck at limits.
I'm going to state the rules for infinite limits first.
1. If the degree of the top equals the degree of the bottom the answer is the top coefficient over the bottom coefficient.
For example, lim x>infinity x^3/4x^3 + 2 = 1/4
2. If the degree of the top is greater than the degree of the bottom, the answer is + or - infinity
Ex: lim x>infinity x^4 -3x^2/ x + 1 = infinity
3. If the degree of the top i less than the degree of the bottom, the answer is 0.
Ex: lim x>infinity x/x^3 + 2 = 0

These are pretty simple rules that everyone should recognize.

Also, i get linearization in my notes but i'm not exactly sure if i know how to do a problem of it.

One thing i am completely comfortable with is problems like these:

The radius, r, of a circle is increasing at a rate of 3 centimeters per minute. Find the rate of change of area, A, when the radius is 5.

First i write down my given:
A =pir^2
dr/dt = 3
r = 5
dA/dt = ?

So take the derivative of the formula.
dA/dt=pi2r(dr/dt)
now plug in:
dA/dt = pi(2)(5)(3)
dA/dt = 30pi

Atleast out of all of this i understand one thing..

On a serious note, if anyone is up for being a tutor please let me know.