Eng Jun Jie's answer to :)'s Secondary 3 A Maths Singapore question.
Why q is equal to 1?
q corresponds to the time when the ball reaches the max height.
Detailed explanation
Consider a quadratic equation y=-a(x-h)²+k
(x-h)²≥0 for all values of x(anything you square it you will get zero or a positive value)
For maximum y, (x-h)²=0, if not y=k- (smt positive) will not give maximum y value, which is k.
For (x-h)²=0, x=h
Therefore, we can conclude that y is max when x=h
Detailed explanation
Consider a quadratic equation y=-a(x-h)²+k
(x-h)²≥0 for all values of x(anything you square it you will get zero or a positive value)
For maximum y, (x-h)²=0, if not y=k- (smt positive) will not give maximum y value, which is k.
For (x-h)²=0, x=h
Therefore, we can conclude that y is max when x=h
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