Eric Nicholas K's answer to Skr's Secondary 3 A Maths Singapore question.
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The water jet must spray to at least a height of 10 m.
Two cases are possible.
One, the water reaches a maximum height of 10 m (i.e. the curve intersects the line y = 10 at only one point).
Two, the water passes a height of 10 m, attains a maximum height and then falls to 10 m (i.e. the curve intersects the line y = 10 at two distinct points).
Combine both cases and you have b2 - 4ac >= 0.
Two cases are possible.
One, the water reaches a maximum height of 10 m (i.e. the curve intersects the line y = 10 at only one point).
Two, the water passes a height of 10 m, attains a maximum height and then falls to 10 m (i.e. the curve intersects the line y = 10 at two distinct points).
Combine both cases and you have b2 - 4ac >= 0.
Date Posted:
5 years ago
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