\fProblem #6: et Let f(x) = 1 + 4x . On what interval is f increasing? (A) (- - In 3, 00) (B) (-= In 4, 00) (C) (= In 4, 00) (D) (-20, = In 4) (E) (-oo, - - In 4) (F) (-oo, - - In 3) (G) (-20, - In 3) (H) ( - In 3, 00)Problem #9: Suppose that the derivative of a function f is given by for} =.1'2{x 213 {x 31-7 (x 4)? Find the xcoordinates of the local minimum points of f. (A) 2 only (B) O and 2 only (C) O and 4 only (D) 2 and 4 only (E) 3 and 4 only (F) 3 only (G) 2 and 3 only (H) 0 and 3 only Problem #4: Consider the function f given below. x-+1 if -1 (5 - 3x).Problem #1: Which of the following is equal to tanh(In x)? 2x x -+ 1 (A) 2x + 1 x- +1 (B) x - 1 2x - 1 (F) x- + 1 x - + 1 (C) x (D) 2x + 1 (E) 2x 2 + 1 (G) - 1 (H) 2xProblem #7: Let f(x) =x7 Inx. On what interval is f concave down? (A) (e-42/13, 20) (B) (0, e-13/42 ) (C) (0, e13/42 ) (D) (e13/42, 0) (E) (e-13/42, 90) (F) (0, 00) (G) (0, e42/13 ) (H) ( @42/13, 60)