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Prove the trignometric identity by first proving the left side is equal to the right side and then proving the right side is equal to the left side.

 

\(cot(\Theta )+tan(\Theta )=sec(\Theta )csc(\Theta )\)

 May 31, 2016

Best Answer 

 #1
avatar+128475 
+5

cot θ +  tan θ  =

 

cos θ/ sin θ  +  sin θ/ cos θ      get a common denominator  of sin θ  cos θ

 

[cos^2 θ   + sin^2 θ] /  [ sin θ  cos θ]

 

1 / [ sin θ  cos θ]  =

 

[1/ sin θ] * [ 1 / cos θ ] =

 

csc θ  sec θ   =   the RHS

 

To prove the other part, we can just reverse the steps above

 

sec θ  csc θ   =

 

1/cos θ  * 1/ sin θ       = 

 

1/ [cos θ sin θ] =

 

[sin ^2  θ + cos ^2 θ] /  cos θ sin θ]  =

 

[sin^2 θ]/ [ sinθ cosθ]   + [cos^2 θ]/ [ sin θ cos θ]  =

 

sin θ / cos θ   +   cos θ / sin θ  =

 

tan θ   + cot θ   = the LHS

 

 

cool cool cool

 May 31, 2016
 #1
avatar+128475 
+5
Best Answer

cot θ +  tan θ  =

 

cos θ/ sin θ  +  sin θ/ cos θ      get a common denominator  of sin θ  cos θ

 

[cos^2 θ   + sin^2 θ] /  [ sin θ  cos θ]

 

1 / [ sin θ  cos θ]  =

 

[1/ sin θ] * [ 1 / cos θ ] =

 

csc θ  sec θ   =   the RHS

 

To prove the other part, we can just reverse the steps above

 

sec θ  csc θ   =

 

1/cos θ  * 1/ sin θ       = 

 

1/ [cos θ sin θ] =

 

[sin ^2  θ + cos ^2 θ] /  cos θ sin θ]  =

 

[sin^2 θ]/ [ sinθ cosθ]   + [cos^2 θ]/ [ sin θ cos θ]  =

 

sin θ / cos θ   +   cos θ / sin θ  =

 

tan θ   + cot θ   = the LHS

 

 

cool cool cool

CPhill May 31, 2016

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