Question

atabA+btanB=(a+b)tan(A+B)/2 show that cosA/cosB=a/b​

Answer 1

Step-by-step explanation:

Hence, the equation can be written as

After cross multiplying and simplifying, we get

or

If sin(A-B) \= 0, then a cos B = b cos A

I hope this may help you

Answer 2

cosA/cosB=a/b

bcosA=acosB

bcosA-acosB=0

cosc=(a+b)cos(A+B)/2