Question

已知角α终边上一点p的坐标为（3,-4）,求cosα,sinα,tanα的值?

Answer 1

x=3,y=-4,√(x^2+y^2) = 5

cosα = x/√(x^2+y^2)=3/5

sinα = y/√(x^2+y^2)=-4/5

tanα = y/x = -4/3