Question

please solve the problem fast and give, me the correct answer by step by step​

Answer 1

Answer:

I think the question may be wrong...

Step-by-step explanation:

we known that ,

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

given A-B = 3π/4

tan(A-B) = tan(3π/4) = 1

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

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

tanA-tanB =1+tanA tanB-------(1)

LHS = (1-tanA)(1+tanB)

= 1 + tanB - tanA - tanA tanB

=1 -tanA tanB - ( tanA -tanB )

substitute the equation (1)

= 1 - tanA tanB -( 1+ tanA tanB )

= 1 -tanA tanB -1 - tanA tanB

= -2 tanA tanB