gualtieri said:
i need help for these two proving questions
prove that
1-tanxtan2x/1+tanxtan2x = 4cossqrd x-3
and
if 4tan(x-b)= 3tanx
prove that tanb=sin2x/7+cos2x
i cant seem to get the answers for both and they are taking me a while
1. (1 - (tanx . 2tanx/1-tan^2(x))) / (1 + (tanx . 2tanx/1-tan^2(x))) =
((1-tan^2(x) - 2tan^x)/1-tan^2(x)) / ((1-tan^2(x) + 2tan^2(x)/1-tan^2(x)) =
1-3tan^2(x)/1+tan^2(x) = 1-3tan^2(x)/sec^2(x)
= cos^2(x) - 3sin^2(x)
= cos^2(x) - 3(1-cos^2(x))
=4cos^2(x) - 3
For q2, is it sin2x/7 + cos 2x or sin2x/(7 + cos2x)?