are points of local maxima and local minima differentiable.......beacause in graph of mod tan pi/4-x the minima point is not diffrentiable

the diameter of a roller is 84 cm and its length is 120 cm. it takes 500 complete revolution tomove once over to level a playground. find the area of the playground in square m?

Find dy/DX when y=x^sinx+sin-1√x. Please give me the solution of this problem.

If domain of f(x) is [-1, 2], then find the domain of f([x]-x^2+4), where [ ]denotes greatest integer function.

Solve the differential equation y’’+2ty’-4y=1, y(0)=y’(0)=0.

Example 20. (i) In a AABC, find the maxima and minima of u = sin A sin B sin Cwhere A + B + C = T(ii) In a plane triangle ABC, find the maximum value of cosA cosB cosC.