Prove the identity cos thetatan theta cot theta csctheta Fo
Prove the identity cos theta(tan theta + cot theta) =csctheta For each step in your solution, carefully document what you are doing. State the identity, formula, or property you are using.
Solution
cos(tan +cot)
=cos((sin/cos) +(cos/sin)) ...............step 1)write tan as sin/cos ,cot as cos/sin
=cos((sin2 +cos2)/cossin))...............step 2) make compound fraction
=cos(1/cossin)).....................................step3)sin2 +cos2 =1 is the identity
=(cos/cossin)).......................................step 4) cancel out cos
=1/sin
=csc.........................................................step 5)rewrite 1/sin as csc
so cos(tan +cot)=csc
