Question

tanθ为5/4sinθ为多少cosθ为多少

Answer 1

tanθ=sinθ/cosθ=5/4

cosθ=(4/5)sinθ

因为：sin²θ+cos²θ=1

则：sin²θ+(16/25)sin²θ=1

sin²θ=25/41

sinθ=±5√41/41

cosθ=±4√41/41

所以：

（1）sinθ=5√41/41;cosθ=4√41/41

（2）sinθ=-5√41/41;cosθ=-4√41/41