若tan^2A+2tanA=3,则∠A=?
问题描述:
若tan^2A+2tanA=3,则∠A=?
答
tan^2A+2tanA=3
(tanA-1)(tanA+3)=0
tanA=1或者-3
tanA=1时,A=kπ+π/4
tanA=-3时,A=kπ-arc tan3
即是A=kπ+π/4或者kπ-arc tan3
答题完毕,