Given that the function y = 2Sin (Wx + Fei) is an even function (w ＞ 0,0 ＜ Fei ＜ π), the distance between two adjacent symmetry axes of an image is π 2, and f (π 9) is obtained After the image of the function is shifted to the right by π - 6 units, the decreasing interval of the function is obtained

Given that the function y = 2Sin (Wx + Fei) is an even function (w ＞ 0,0 ＜ Fei ＜ π), the distance between two adjacent symmetry axes of an image is π 2, and f (π 9) is obtained After the image of the function is shifted to the right by π - 6 units, the decreasing interval of the function is obtained

The function y = 2Sin (Wx + Fei) is even, 0 < Fei < π, then Fei = π / 2
The distance between two adjacent symmetry axes is t / 2, so t = π, w = 2
y=2sin(2x+π/2)=2cos2x
F (π - 8) = radical 2
The function y = 2cos (2x - π / 3) is obtained when the image of the function is shifted to the right by π - 6 units
From 2K π less than or equal to 2x - π / 3 less than or equal to 2K π + π
The decreasing interval [K π + π / 6, K π + 2 π / 3] can be obtained