10-2!

Formulas:

~tan(A+B)= (tanA + tanB)/(1-tanAtanB)

~tan(A-B)= (tanA- tanB)/(1+tanAtanB)

YOU MUST USE THE FORMULAS!

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Ex.1: Suppose tanA=2 and tanB=6; Find tan(A+B):

tan(A+B)=(2+6)/(1-2*6)

=8/1-12

tan(A+B)=-8/11

Ex.2: Suppose tanA=1/2 and tanB=3/4; Find tan(A-B):

tan(A-B)=(1/2-3/4)/(1+1/2*3/4)

=(-1/4)/(1+3/8)

-1/4/11/8= -8/44

tan(A-B)=-2/11

Ex.3: Suppose tanA=3 and tanB=5; Find tan(A-B):

tan(A-B)=(3-5)/(1+3*5)

=-2/1+15

=-2/16

tan(A-B)=-1/8

Ex.4: Suppose tanA=1/6 and tanB=2/3; Find tan(A+B):

tan(A+B)=(1/6+2/3)/(1-1/6*2/3)

=5/6/8/9

=45/48

tan(A+B)=15/16