Let f(x) = √(x2 + 5) . Then f'(x) is (x/√(x2 + 5) ) , if f''(x) is ___ and f''(4) is ___.
a) f''(x) = -5/(x2 + 5) (3/2) ; f''(4) = -5/√(21)
b) f''(x) = 5/(x2 + 5) (3/2) ; f''(4) = 5/√(21)
c) f''(x) = -5/(x2 + 5) (3/2) ; f''(4) = 5/√(21)
d) f''(x) = 5/(x2 + 5) (3/2) ; f''(4) = -5/√(21)