Find the interval in which the function `f` given by `f(x)=sin2x+cos2x, 0lexlepi` is strictly decreasing.

Find the interval in which the function f given by f(x)=sin2x+cos2x,0<=x<=pi is strictly decreasing.

Find the intervals in which the function f given by f(x)=sinx+cosx, 0lexle2pi is strictly increasing or strictly decreasing.

Find the intervals in which the function given by f(x)=sin x+cos x, 0le x le 2pi is strictly increasing.

Find the intervals in which the function f given by f(x)=sinx-cosx,0lexle2π is strictly increasing or strictly decreasing.

Find the intervals in which the function f given by f(x)=sin x-cos x, 0 lt x lt 2 pi is strictly increasing or strictly decreasing.

Find the intervals in which the function f given by f(x)=sinx+cosx ,\ \ 0lt=x\ lt=2pi is strictly increasing or strictly decreasing.

Find the intervals in which the function f given by f(x)=sin x+cos x,quad 0<=x<=2 pi is strictly increasing or strictly decreasing.