Question

Use trigonometric Identities to solve:
1.sinx/1+sinx - sinx/1-sinx?
2.(sinx+cosx)^2/1+2sinxcosx?

Answer 1

= (sin(x)-sin^2(x)-sin(x)-sin^2(x))/1-sin^2(x)
= -2sin^2(x)/cos^2(x)
= -2tan^2(x)

Answer 2

= sin^2(x)+cos^2(x)+2sin(x)cos(x)/1+2sin(x)cos(x)
= 1+2sin(x)cos(x)/1+2sin(x)cos(x)
=1

Answer 3

(sin(x)-cos(x))^2
=[sin(x)-cos(x))(sin(x)-cos(x)]
=sin^2(x)-2sin(x)cos(x)+cos^2(x)
=1-2sin(x)cos(x)

Answer 4

Thanks guys! I had the first one right :)