tanα=2,则
2sinαcosα+1/cos^2α
=2sinαcosα/(cos^2α+sin^2α)+(cos^2α+sin^2α)/cos^2α
=2tanα/(1+tan^2α)+(1+tan^2α)
=4/5+5
=5.8
(2sin阿尔法cos阿尔法+cos方阿尔法)分之一
tanα=2,则
1/(2sinαcosα+cos^2α)=(cos^2α+sin^2α)/(2sinαcosα+cos^2α)
=(1+tan^2α)/(2tanα+1)
=(1+2^2)/2*2+1)
=1