Does (1) function y=f(x) satisfy the meaning of f(x0)=0? Fingers? When the independent variable x=x0, the function value is 0.

And the function has an extreme value at x0? The conclusion should be? Is the derivative of f(x) when x0 = 0.

(3) As long as the linear polar coordinate equation is transformed into rectangular coordinate equation, the distance formula from point to line can be used.

? It is suggested that it is faster to solve this diagram by combining the mirror image method of polar coordinates.

(2)