Help me on this problem please and show your work.

3. ( 12 points ) The human heart goes through cycles of contraction and relaxation (called systoles). During these cycles , blood pressure goes up and down repeatedly ; as the heart contracts, pressure rises and as the heart relaxes ( for a split second) , the pressure drops. For a particular patient, the function P(t) = 100 + 20 cos(1tt/35) (where t is measured in minutes) approximately models these cycles. [Blood pressure is measured in units of millimeters of mercury (mmHg).] a. What is the period of this function ? b. Find P'(t) and describe what this tells us. c. During what intervals in one cycle is the pressure increasing or decreasing ? ( hint, first find where P' (t)=0 ) d. What is the largest rate of increase ? Use units in your answer. What is the smallest rate of increase