Posted by Marrion on .
Given that a^2+b^2=2 and that (a/b)= tan(45degee+x), find a and b in terms of sinx and cosx.
I don't know what i'm supposed to do, and i don't come to an answer! Help, thanks!
my workings:
tan(45+x)= (1+tanx)/(1tanx)
a/b = (1+tanx)/(1tanx)
a(1tanx)=b(1+tanx)
i square both sides...
a^2(1tanx)^2 = b^2(1+tanx)^2
a^2 + b^2 = 2
a^2 = 2  b^2
substitute:
(2b^2)(1tanx)^2 = b^2(1+tanx)^2
I don't know if im on the right track, but i don't seem to come to an answer when i expand the whole equation!

Trigonometry 
MathMate,
From:
a(1tanx)=b(1+tanx)
multiply both sides by cos(x) to get
a(cos(x)sin(x))=b(cos(x)+sin(x))
Now square and simplify. The product terms will cancel out after you substitute b²=(2a²) to give you a in terms of sin(x) and cos(x).
You can do similarly for b.