Question

tanθ为4/5sinθ为多少cosθ为多少

Answer 1

sinθ/cosθ=tanθ=4/5

sinθ^2+cosθ^2=1

令sinθ=4x,cosθ=5x

(4x)^2+(5x)^2=1,x=1/√41

sinθ=4/√41

cosθ=5/√41