Question

sinx/cosx+cosx/sinx=4 怎么算啊

Answer 1

sinx/cosx + cosx/sinx = 4

sin²x/(sinxcosx) + cos²x/(sinxcosx) = 4

(sin²x + cos²x)/(sinxcosx) = 4

1/(sinxcosx) = 4

sinxcosx = 1/4

sin2x = 1/2

2x = 2kπ + π/6 或2kπ + 5π/6

x = kπ + π/12 或 kπ + 5π/12 ,k ∈Z