If A + B = 225° then (1 + tanA)(1+tanB) =

Question

Its about trigonometry. I need formulas.

Answer 1

tan(A+B) = [tanA + tanB]/[1- tanAtanB]

 

Since A+B = 225°, tan (A+B) = 1

 

So, tanA + tanB = 1 - tanAtanB

 

Therefore, tanA + tanB + tanAtanB = 1

 

(1 + tanA)(1+tanB) = 1 + tanA + tanB + tanAtanB

 

                              = 1 + 1 = 2