Determining Concavity In Exercises 3-14, determine the open intervals on which the graph O of the function is concave upward or concave downward. 3. f(x) = x2 - 4x+ 8 3x2 5. f ( x ) = x4 - 3x3 24 7. f(x) 10 11. f() 12. 2x 13. y = 2x - tan x. 2 2 14. y = x sin x Finding Points of Inflection In Exercises 15-36, find the points of inflection and discuss the O concavity of the graph of the function. 15. f(x) = >3 - 9x2 + 24x - 18 16 fly) = -x3 + 6.x2 - 5 17. f(x) = 2 - Zx 19. f(x) = x(x - 4)3 21. f(x) = xx + 3 23. f() x 25. f(x) = sin ~, [0, 4x] 26. f(x) = 2 csc 3X (0. 271) 27. f(x) = sec x (0. 47) (() = 2 sin x + sin 2x. [0. 27] 30. / (x) = x + 2 cos .x, [0, 271] 31. y = e-3/x 32. y = 3(ex - ( x)