Posted by T.Gracken on September 28, 2002 at 20:11:51:
In Reply to: could someone help me Brad Paul's answer doesn't work posted by June on September 28, 2002 at 19:37:25:
: : : the question is find sin 2, cos 2, tan 2.
: : : tan x = -sqrt 2 and pi/2 < x < pi
: : : How do you find cos and sin when you just know tan, I can't find any examples in the book. This is the full question. I know how to go on from there.
: : : Their answer is
: : : sin 2 x =-2((sqrt2)/3)
: : : cos 2 x = -1/3
: : : tan 2 x = 2(sqr(2))Ju
: : Use:
: : tan(2 x)=2 tan(x)/(1-tan2(x))
: : Along with what I wrote before.