1, generally speaking, first calculate the function of area about x, then formulate it and add a constant to this function in a completely flat way. If a maximum value is required, a completely flat road is preceded by a negative sign, so when this completely flat road takes 0, there is a maximum value. (Note whether x can get the corresponding value when the completely flat mode is equal to 0. )

2, first calculate the function about the area of X, and then you can draw the image, which is very intuitive, and pay attention to the definition domain of X.

3. First, calculate the function of the area about X. If this resolution function is complicated, you can try to directly see how much X has gone when the area is the largest.

4. If you have studied calculus, first calculate the function of area about x, and then take the derivative of this function. Generally speaking, the value of x corresponding to the derivative function of 0 is the value corresponding to x when this function takes the maximum value. Quadratic derivative function is greater than 0, which is the minimum value, quadratic derivative function is less than 0, which is the maximum value, and quadratic derivative function is equal to 0, which is the turning point of higher order function.