siddharth gupta
Last Activity: 11 Years ago
cos(a+b)=4/5i.e cos-14/5=a+b i.e tan-13/4=a+b(can be calculated by considering a right triangle)......(1)
similarly sin-15/13=a-b and hence tan-15/12=a-b(calculated as above)......(2)
add (1)and(2)
a+b+a-b=2a=tan-15/13+tan-15/12=tan-156/33i.e tan2a=56/33.
thanks
siddharth gupta