8. Find the second derivative of y by implicit differentiation from the equation(1 Point) 4x2 + 8y- = 36 O 32ty 16v3 4 9. Find the partial derivative with respect to x of the function (1 Point) xy - 5y + 6 Oy -5 O 2xy Oxy - 5y 10. Find the second derivative of [, (1 Point) x3 - 5x2 + x =0 O 10x - 5 9 6x - 10 3x + 10 O 3x2 - 5x14. What is the first derivative of y = arc sin 3x.(1 Point) (1+9x2) 3 O O 3 (1+9x2) 15. If y = x (In x), find (1 Point) dy adx 2 O 16. The sum of two positive numbers is 50. What are the numbers it their product is to be the largest possible. [T (1 Point) 28 and 22 20 and 30 25 and 25 24 and 26 17. A triangle has variable sides x y, z subject to the constraint such that the perimeter is fixed to 18 cm. What is the maximum possible area for the triangle?(1 Point) 18.71 co 15.59 or 14.03 on 17.15 car18. A box is to be constructed from a piece of zinc 20 sq. in by cutting equal squares from each corner and turning up the zinc to form the side. What is the volume of the largest box that can be constructed? (1 Point) O 599.95 cu in 592.59 cu in 622.49 cu in 579.50 cu in 19. A normal window is in the shape of a rectangle surmounted by a semi-circle. What is the ratio of the width of the rectangle to the total height so that it will yield a window admitting the most light for a given perimeter?(1 Point) OI O2 20. Determine the diameter of a closed cylindrical tank having a volume of 11.3 cu m. to obtain minimum surface area. [I (1 Point) 1.64 O 2.44 2.68 1.22