Barrons AP Calculus - David Bock

Use the following graph for Questions 88–90.

88. At which labeled point do both equal zero?
    (A) P
    (B) Q
    (C) R
    (D) S
    (E) T


89. At which labeled point is positive and equal to zero?
    (A) P
    (B) Q
    (C) R
    (D) S
    (E) T