.
A diver jumps from a springboard. The function h(t) = −5t² + 8t + 4
shows the height of the diver above the water, in meters, t seconds
after the diver leaves the springboard. What time, in seconds, did the
diver start his descent?
Ⓐ 0.4
Ⓑ 0.8
Ⓒ 2
Ⓓ 4
~~~~~~~~~~~~~~~
The diver starts his descent at the highest point, so we need find the vertex
of the parabola
= , where a= -5 is the coefficient at t^2;
b= 8 is the coefficient at t.
= = = 0.8 seconds. ANSWER
Solved.
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On finding maximum/minimum of a quadratic function see the lessons
- HOW TO complete the square to find the minimum/maximum of a quadratic function
- Briefly on finding the minimum/maximum of a quadratic function
- HOW TO complete the square to find the vertex of a parabola
- Briefly on finding the vertex of a parabola
in this site.
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