Question

cosX等于2分之根号2,满足x大于4派小于4派的解

Answer 1

cosx=根号2/2

x=π/4＋2kπ或者x=-π/4＋2kπ

因为x大于-4π小于4π

所以x=π/4－4π x=π/4－2π x=π/4 x=π/4＋2π

x=-π/4－2π x=-π/4 x=-π/4＋2π x=-π/4＋4π