Question

if a+b=135 degrees,then (1-tanA) (1-tanB)​

Answer 1

Answer:

2

Step-by-step explanation:

A+B = 135

Tan(A+B) = Tan 135

// But Tan(A+B) = TanA + TanB / 1 - TanA TanB;

//Tan 135 = Tan(90+45) =  - Cot45 = -1

TanA + TanB / 1 - TanA TanB = - 1

TanA + TanB  = - 1 + TanATanB

TanATanB - TanA - TanB = 1

/Add one on both sides.

TanATanB - TanA - TanB + 1 = 1 +1

(1  - TanB) - TanA(1 - TanB)  = 2

(1 - TanB) ( 1 - TanA) = 2