Question

16- If f(x) = 2x/1+x², prove that f(tan thita )=sin 20 is 2 thita​

Answer 1

Answer:

04-Nov-2020 — If f(x)=(2x)/(1+x^2)\ , show that f(tantheta)=sin2theta) ... f(tanθ)=2tanθ(1+tan2θ)=2tanθsec2θ=2sinθcosθ×cos2θ=2sinθ.cosθ=sin20.

Answer 2

Answer:

Answer

f(x)=

1+x

2

2x

now, f(tanθ)=

1+tan

2

θ

2tanθ

=

sec

2

θ

2tanθ

∴ f(tanθ)=2

cosθ

sinθ

×cos

2

θ

=2sinθcosθ

f(tanθ)=sin2θ