Exercise 4.7.1 Find aformulafor the derivative y' at the point (x, y): (h) y=xXT2 (b) 4-xy+y2= 7 218 (h) Derivatives (e) v'i+v.39 (D tan(x/y) x + y (j) xsec(y) In(sinx) Exercise 4.7.2 Use logarithmic differentiation to find the derivative of y. (2r2 Exercise 4.7.4 The graph of the equation x2 xy 4- Y2 = 9 is an ellipse. Find the lines tangent to this curve at the two points where it intersects the x-axis. Show that these lines are parallel. Exercise 4.7.10 Find an equation for the tangent line to (x2 + y2)2 = Y2 at a point (XI,YI) on the Curve, with x, O, l, l. (This Curve is a lemniscate.) Exercise 4.7.13 Differentiate the function _f(x) (x+ I