Question

tan(4分之派－阿尔发）＝3,则cot阿尔发＝?

Answer 1

tan(π/4-α)

=(tanπ/4-tanα)/(1+tanπ/4tanα)

=(1-tanα)/(1+tanα)=3

1-tanα=3+3tanα

tanα=-1/2

cotα=1/tanα=-2