Question

65
30. If A + B = 135°, then the value of (1 -tan A) (tan B - 1) is
2) 2
31
65
So as
2) 65
4)
leaved) 1
Pud
4) 1​

Answer 1

Answer:

- 2

Step-by-step explanation:

A+B = 135°

Tan(A+B) = Tan135°

TanA + TanB / 1 - TanATanB = Tan(90 + 45)

TanA + TanB / 1 - TanATanB  = - Cot45

TanA+ TanB = - 1 ( 1 - TanATanB)

TanA + TanB = TanATanB - 1   ---------- [1]

Now

(1 - TanA) (TanB - 1) = TanA + TanB - TanATanB -1

= TanATanB - 1 - TanATanB - 1

= - 2.