10-2

Today I'm go to explain how to do chapter 10, section 2. This is the sum and difference for tangent. There's only two formulas for this secction. They're almost the same thing except the sign changes. Formulas: tan(alpha+beta) = tan(alpha) + tan(beta)/1-tan(alpha)tan(beta) tan(alpha-beta) = tan(alpha) - tan(beta)/1+tan(alpha)tan(beta) REMINDER: You do not plug in for formulas like the ones above, you replace. Okay, time for some examples!!!! Suppose tan alpha = 1/3 and tan beta = 1/2 Find tan(alpha+beta) = (1/3 + 1/2)/(1-(1/3)(1/2)) =( 2/6+3/6)/(1-1/6) = (5/6)/(5/6) = 1 Suppose tan alpha = 4/3 and tan beta = -1/2 Find tan(alpha+beta) = (4/3+(-1/2))/(1-4/3(-1/2) =(8/6+(-3/6))/(1-(-4/6) =(5/6)/(10/6) =1/2