Write each of the following in the simplest form:
Assume x = tanθ
= tan–1
= tan–1
= tan–1
= tan–1
= tan–1
Cos θ = 1 – 2 sin2
and sinθ = 
⇒ 1 – cosθ = 2 sin2
= tan–1
= tan–1
= tan–1(tan
)
= 
But θ = tan–1x.
∴ 
Therefore, the simplification of given equation is 
7