15 Matching Annotations
  1. Mar 2020
    1. We then differentiate the outside function leaving the inside function alone and multiply all of this by the derivative of the inside function.

      The chain rule written out in a nice organized way to understand.

    1. limx→∞tan−1x=π2limx→−∞tan−1x=−π2

      This is because the trig function of tan has vertical asymptotes, so it would make sense for the inverse to have horizontal asymptotes at the same values.

    2. cos2y+sin2y=1

      You can manipulate this a few ways to get a trig identity you need for a problem. An example would be if I need my terms to be in terms of cos and I had sin^2(y) in my problem, I would just replace sin^2(y) with -cos^(y)-1

  2. Jan 2020
    1. DO NOT CANCEL AN xxx FROM BOTH SIDES!!

      I don't think we are ever supposed to cancel out a variable when we are solving for variables. Cancelling constants is fine because it just reducing or simplifying.

    1. Sometimes, there will be many solutions as there were in this example.

      This problem is a lot longer than it looked at first. But it is important to go through the problem thoroughly to make sure we don't miss any solutions.