Pleaseee HELPP mee…… plz

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

The formula for the lateral area of a right cone is la = rs, where r is the radius of the base and s is the slant height of the cone. which are equivalent equations?

Which one ? is the answer and how to find this answer