1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Trig functions that i have to memorize?

  1. Mar 22, 2005 #1
    I am taking calculus and math 12 at the same time. Now we are doing limits of trigonometric functions, but i know nothing about it. What are some important trig functions that i have to memorize?

    Ex. I have no idea how to do these
    lim (tanx-sinx)/xcosx
  2. jcsd
  3. Mar 22, 2005 #2
    Your book probably has a table of the concepts you need such as.

    d(x)sinX = cosX
    d(x) cosx = -sinx
    d(x) tanx = sec^2x
    d(x) secx = secx tanx
    d(x) cotx = -csc^2x
    d(x) cscx = -cscx cot x

    Are these what you were looking for?
  4. Mar 22, 2005 #3
    To do that limit, you should use L'Hopital's Rule.

    [tex]\lim_{x\rightarrow\infty} \frac{\tan0 - \sin0}{0*\cos0} [/tex] is indeterminate... you get 0/0. Differentiate the top and the bottom and try the limit again. If that doesn't work, then try it once more... If this continues to fail, use another approach.

  5. Mar 22, 2005 #4
    Know how to find the limit of sinx/x as x-> 0, the other trig identities dont need much thought, usually rearranging or using trig identities yields you an easy limit.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Trig functions that i have to memorize?
  1. Trig Function (Replies: 4)

  2. Trig Function (Replies: 7)