Question

若tan(A+B)=2/5,tan(B-pai/4)=1/4,那么tan(A+pai/4)的值是多少.

Answer 1

解:tan[A+(π/4)]=tan{(A+B)-[B-(π/4)]} tan{(A+B)-[B-(π/4)]}={tan{(A+B)-tan[B-(π/4)]}/{1+〈tan{(A+B)×tan[B-(π/4)]〉}=[(2/5)-(1/4)]/[1+(2/5)×(1/4)]=(3/20)/(22/20)=3/22