please do all the questions for an upvote

y 4. Given that = 4 z determine the approximate change in using partial differentiation if x increases by 4%, y by 7% and z decreases by 3%. (4 marks) 2 4 dy 15% 8. racos 20 ydydo. Evaluate SS de x (4 marks) A(-343) + B - ( 9. Use Demoivres theorem to expand cos 50. 94 cosaak idrolo (4 marks) (more