Question

Tan22° + tan23° tan22°. tan23° = 1 prove that ​

Answer 1

Formula:(from trigonometry)

Tan(A+B)=(tanA+tanB)/(1-tanA*tanB)

Let A=22 degrees,B=23 degrees

Tan(22+23)=(tan22+tan23)/(1-tan22*tan23)

From trigonometry we know tan45=1

Therefore tan(45)=1=(tan22+tan23)/(1-tan22tan23)

=> 1-tan22tan23=tan22+tan23

=> tan22+tan23+tan23tan22 =1

Hence proved