Question #857b8

1 Answer
Feb 11, 2018

Kindly refer to a Proof in the Explanation.

Explanation:

tanx/(1-cotx)+cotx/(1-tanx),

=tanx/(1-1/tanx)+(1/tanx)/(1-tanx),

=tan^2x/(tanx-1)-1/{tanx(tanx-1)},

=(tan^3x-1)/{tanx(tanx-1)},

={cancel((tanx-1))(tan^2x+tanx+1)}/{tanxcancel((tanx-1))},

=tan^2x/tanx+tanx/tanx+1/tanx,

=tanx+1+1/tanx,

=1+{sinx/cosx+cosx/sinx},

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

=1+1/(sinxcosx),

=1+1/cosx*1/sinx,

=1+secxcscx, as desired!