Homework Help Forum: Trigonometry

Posted by Marrion on Sunday, September 27, 2009 at 2:11am.

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 dont come to an answer! Help, thanks! my workings: tan(45+x)= (1+tanx)/(1-tanx) a/b = (1+tanx)/(1-tanx) a(1-tanx)=b(1+tanx) i square both sides... a^2(1-tanx)^2 = b^2(1+tanx)^2 a^2 + b^2 = 2 a^2 = 2 - b^2 substitute: (2-b^2)(1-tanx)^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, Sunday, September 27, 2009 at 8:48am

  From: a(1-tanx)=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=(2-a²) to give you a in terms of sin(x) and cos(x). You can do similarly for b.

  
  

Answer this Question

First Name:
School Subject:
Answer: