How do you prove #sintheta=+-tantheta/(sqrt(1+tan^2theta))#?

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Answer 1 · 2018-03-08T18:27:14

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#RHS: +-tan theta/(sqrt(1+tan^2theta))#

#=+-tan theta/sqrt(sec^2theta)#

#=tan theta/sec theta#->since we are squaring #sectheta# the result is always positive so we drop the negative sign.

#=(sin theta/cos theta)/(1/costheta)#

#=sin theta/cancelcos theta * cancelcos theta/1#

#=sin theta#

#=LHS#