Painting can solve everything. You just need to remember the original basic diagrams of sinx, cosx and tanx. For a given domain, take several points (generally five points on average, 0, 1/2π, π, 3/2π, 2π) and calculate the function values respectively. Then draw points and connect them with smooth curves, which can be simply saved, and the value range is the value range of Y axis. As shown in the figure: range-2,2

"+1" means moving up along the y axis 1, and "-1" means moving down 1. In fact, you can find it when you bring the value in. For example, when X=0, y = 2sinx = 0; When there is "+1", when x=0, y =1+2sinx =1; When y changes from 0 to 1, move 1 upward.

In addition, we should pay attention to whether the function has parity. If so, it is enough to draw half and the other half symmetrically.

If the function has periodicity, you only need to draw a period, and other parts will be extended according to the period.

(Forgot to adopt)