Question

A and B are two positive angles less than 45° and cos(A+B)=4/5,sin(A-B)=5/13,find tan2A

Answer 1

Answer:

Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation:

given,

cos(A+B) = 4/5, thus tan(A+B)=3/4.

sin(A-B)=5/13,thus tan(A-B)=5/12.

then tan(2A)=tan((A+B)+(A-B))

=(tan(A+B)+tan(A-B))/(1-tan(A+B)tan(A-B))

=(3/4+5/12)/(1-(3/4)(5/12))

=56/33.