The periodicity is f(x)=f(x+T)t is his periodicity, and the parity is f(x)=f(-x), etc. odd function is symmetrical about the origin, even function is symmetrical about y axis, the domain of even and odd function must be symmetrical about the origin, and odd function f(0)==0.

For the 1 problem, use method of substitution to make x- 1 equal to t and f(t)=F(-t). . Then we know that we can see that the point (1, 0) is an extreme point, and because it is an even function, the available period for drawing is 2.

2.。 . . I really don't know what two things add up to. This is meaningful.

In addition, the best function is drawing, and it is also necessary to use five-point method and extreme value method to substitute.

To understand these three problems, it is best to take a closer look at the images of trigonometric functions cos and sin, which contain all the properties.