Using the vertex of the quadratic equation, it is found that:
The rocket will reach its peak height of 345 meters above sea level at 6.53 seconds.
What is the vertex of a quadratic equation?
A quadratic equation is modeled by:
[tex]y = ax^2 + bx + c[/tex]
The vertex is given by:
[tex](x_v, y_v)[/tex]
In which:
[tex]x_v = -\frac{b}{2a}[/tex]
[tex]y_v = -\frac{b^2 - 4ac}{4a}[/tex]
Considering the coefficient a, we have that:
- If a < 0, the vertex is a maximum point.
- If a > 0, the vertex is a minimum point.
In this problem, the equation is given by:
h(t) = -4.9t² + 64t + 136.
The coefficients are a = -4.9 < 0, b = 64, c = 136, hence the instant of the maximum height is given by, in seconds:
[tex]t_v = -\frac{64}{2(-4.9)} = 6.53[/tex]
More can be learned about the vertex of a quadratic equation at