Write each of the following in the simplest form:

Put x = cos θ


= sin–1(2tan–1)


1 – cosθ = 2 sin2 and 1 + cos θ = 2 cos2


= sin–1(2tan–1)


= sin–1(2tan–1)


= sin–1(2tan–1(tan))


= sin–1()


= sin–1(θ)


But θ = cos–1x


The above expression becomes sin–1(cos–1x)


7