A ball is thrown in the air from the top of a building. Its height, in meters above ground, as a function of time, in seconds, is given by h(t)=−4.9t^2+5t+3. How many seconds does it take to reach maximum height? Enter the answer with at least 3 decimal places.

Respuesta :

Answer:

The number of seconds it takes for the ball to reach the maximum height is 0.5102

Step-by-step explanation:

we have

[tex]h(t)=-4.9t^{2}+5t+3[/tex]

where

h(t) is the height in meters above the ground

t is the time in seconds

This is a vertical parabola open downward

The vertex is a maximum

The number of seconds it takes for the ball to reach the maximum height is equal to the x-coordinate of the vertex

Convert the given function to vertex form

[tex]h(t)=-4.9t^{2}+5t+3[/tex]

Factor -4.9

Complete the squares

[tex]h(t)=-4.9(t^{2}-\frac{5}{4.9}t+\frac{5^2}{9.8^2})+3++\frac{5^2}{9.8^2}(4.9)[/tex]

[tex]h(t)=-4.9(t^{2}-\frac{5}{4.9}t+\frac{5^2}{9.8^2})+3+1.2755[/tex]

[tex]h(t)=-4.9(t^{2}-\frac{5}{4.9}t+\frac{5^2}{9.8^2})+4.2755[/tex]

Rewrite as perfect squares

[tex]h(t)=-4.9(t-\frac{5}{9.8})^{2}+4.2755[/tex]

The vertex is the point [tex](\frac{5}{9.8},4.2755)[/tex]

Divide the fraction

[tex](0.5102,4.2755)[/tex]

therefore

The number of seconds it takes for the ball to reach the maximum height is 0.5102