Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Couple Trig Problems

  1. May 5, 2005 #1
    A few trig problems that require the same thing or concept. As always I appreciate the help.

    1) If Tan A=1/3 and Tan B=1/2 show that Tan(1/3 + 1/2) = 1

    (Tan1/2 + Tan1/3) / 1-tan(1/2)tan(1/3)

    I am a little confused with this because I cant use a calculator and am confused on what exactly to do here. I dont know Tan1/2 or Tan 1/3..I know it of pie/2 and pie/3 but its not the same?

    2) Tan(7Pie/4 - 1/3)

    Sort of the same thing, if I figure out what to do with the 1/3 i should be good. The 7Pie/4 = 315 = -1..so is it just Tangent of -4/3?

    Thanks again for taking the time
  2. jcsd
  3. May 5, 2005 #2
    [tex]Tan(A+B) = \frac{\tan A + \tan B}{1-\tan(A)\tan(B)}[/tex]

    You mistook Tan(A) = 1/2 for tan(1/2) = A

    Use the above equation for #2 with [itex] A =\frac{7\pi}{4} \ and \ B = (-1/3)[/tex]
  4. May 5, 2005 #3
    1. Are you sure it's not [tex]Tan(a+b)[/tex].
    2. Combine the fraction
    * Edit sorry posted before i saw whozum's
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook