Question

Show that 2tan inverse = cos inverse ( 1- x square) divided by (1+ x square)

Answer 1

ANSWER:-

tan-1x = y

x= tany

2tan-1x= cos-1 1-x2/1+x2

= cos-1 1-tan2y/1+tan2y

= cos-1(cos2y)

=2y

=2tan-1x

therefore, 2tan-1x = cos-1 1-x2/1+x2