Prove Sin theta= tan theta/ sqrt 1+tan^2 theta. Hint: Solve for sin^2 in number 14.


Here is number 14:
sin^2 theta/ 1-sin^2 theta= tan^2 theta

Respuesta :

If you know all the trig identities you don't need to solve 14. The trig identities you need to know are tan=sin/cos. Sec=1/cos. And 1+tan^2= sec^2
(I'll be replacing theta with x to make it easier to type)

Problem: sinx=tanx/sqrt 1+tanx^2.


Since 1+tanx^2=secx ^2

Sinx=tanx/sqrt secx^2

Sinx=tanx/secx

Now tanx= sinx/cosx and secx=1/cosx
(Sinx/cosx)/(1/cosx). The cosx cancel out leaving sin

So sinx=sinx