Question

The function f(x) = -5x2 + 13x + 6 represents the height, in meters, of a

coin x seconds after it is thrown into the air. What is the maximum
height of the coin?
A 6.25 meters
B. 12 meters
C. 14 meters
D. 14.45 meters
HELPPPPPPP

Answer 1

D

Explanation:

Differentiate the function and set it to zero:

f'(x) = -10x + 13

0 = -10x + 13

x = 1.3 seconds

Plug the x value into f(x):

f(1.3) = -5(1.3)^2 + 13(1.3) + 6 = 14.45 meters