INVERSE FUNCTION FORMULA PART 2

•  2Tan^-1x = Sin^-1( 2x/1+x² ) = Cos^-1( 1-x²/1+x² ) = Tan^-1( 2x/1-x² )

• Sin^-1x + Sin^-1y = Sin^-1( x/√1-y²+y/√1-x² )

• Sin^-1x - Sin^-1y = Sin^-1( x/√1-y²-y/√1-x² )

• Cos^-1x + Cos^-1y = Cos^-1( xy - √1-x²√1-y² )

• Cos^-1x - Cos^-1y = Cos^-1( xy + √1-x²√1-y² )

• Tan^-1x + Tan^-1y = Tan^-1( x + y/1-xy )

• Tan^-1x - Tan^-1y = Tan^-1( x - y/1+xy )

• Tan^-1x + Tan^-1y + Tan^-1z = Tan^-1( x + y + z/1-xy-yz-zx )