If Tan (A+B)=1/3 and Tan(A-B)=2/5,then prove that

Question

A.Tan2A=11/13
B.Tan2B=-1/17

Answer 1

Let
x = arctan(1/3)
y = arctan(2/5)

A+B = x
A-B = y
2A = x+y
tan2A = tan(x+y)
= (tanx+tany)/(1-tanx*tany)
= (1/3 + 2/5)/(1-(1/3)(2/5))
= 11/13

do 2B the same way

Answer 2

Good

Answer 3

WOW....you are very creative ....

Answer 4

It is really very short ans plz put long ans soo that we can understand

Answer 5

Thank you sir

Answer 6

How can he keep arctan 1/3 as x.
X must be kept as 1/3 and while putting the value of x There should be Tanx=Tan 1/3

Answer 7

It is very helpful for me