. What is the formula of tan

(a+b)

Best Answer

Formula of tan(a + b) = (tan a + tan b)/(1 - tan a·tan b).

Proof of Tan(a + b) Identity Using Sin(a+b) and Cos(a+b)

we know, tan(a + b) = sin(a + b)/cos(a + b)

= (sin a cos b + cos a sin b)/(cos a cos b - sin a sin b)

Dividing the numerator and denominator by cos a cos b, we get

tan(a + b) = (tan a + tan b)/(1 - tan a·tan b).

Also check

Related questions