Answer:
30.49 m
Step-by-step explanation:
To obtain the maximum height, we solve for the value x when dy/dx = 0.
Since, y = -5x² + 40x + 20
dy/dx = d[-5x² + 40x + 20]/dx
dy/dx = -10x + 40
Since dy/dx = 0,
-10x + 40 = 0
-10x = -40
x = -40/-10
x = 4
Substituting x = 4 into the equation for y, we have
y = -5x² + 40x + 20
y = -5(4)² + 40(4) + 20
y = -5(16) + 160 + 20
y = -80 + 160 + 20
y = 80 + 20
y = 100 ft
Since y is in feet, we convert to meters.
Since 1 m = 3.28 ft, 100 ft = 100 ft × 1 m/3.28 ft = 30.49 m
So, the maximum height, in meters reached by the projectile is 30.49 m
