Question

高一数学三角函数已知角a的终边上一点P（-√3,m）且sina=√2m/4,求cosa与tana请写出详细过程

Answer 1

tana=-√3m/3

sina=-√3m/3cosa

cosa=-√6/4

sin^2a+cos^2a=1

m^2/8+3/8=1

m^2+3=8

m^2=5

m=±√5

∵cosa>pi/2

∴1>sina>0

∴-√5舍去,m=√5

tana=-√15/3

cosa=-√6/4

sina=√10/4