Post #2

I struggled this week. I’m not completely comfortable with anything we did this week but I think I understood how to find the equation of a tangent line over everything else. To find an equation of a tangent line, you can be giving a point or only giving an x value. If you are only giving an x value, you have to plug in x to find your y and make a point. Next you have to find the derivative of the equation. Once you found the derivative, you plug in for x and get your slope. The last step is to put in point slope form which is y-y1=m(x-x1).
An example of this is:

3x^3+4x^2=5 at (1,12) – you are already giving the point so you can skip step one

Derivative = 9x^2+8x

Plug in x = 9(1)^2+8(1)= 17

Plug into point slope form: y-12=(x-1)

I understand logs from last year and the first column of our page three worksheet but I didn’t understand the derivatives of logs. I know the formula is u prime/ulna but I get confused on the really big problems when you have to do more than one step to solve it. Making a list sort of helps but I end up doing it in the wrong order and my answer usually turns out completely wrong. If I do somehow happen to get the derivative right, I get stuck on the algebra part of the equation. I think I just need more practice on derivatives all together, especially before the test Wednesday. Help if you can and good luck on the test.