Question

两道英文的微积分题目…求教 大致过程和第二题画图就好

Answer 1

y(t) =√[25² - x(t)²]

y'(t) = (1/2){1/√[25² - x(t)²]}*[-2x(t)]*x'(t)

= -x(t)x'(t)/√[25² - x(t)²]

When x = 9,x'(t) = 3,y'(t) = -9*3/(25² - 9²) = -27/12 = -9/4

Apparently the 2nd question is incomplete.