Eric Nicholas K's answer to Candice lim's Secondary 3 A Maths Singapore question.
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Good evening Candice! Here are my workings for this question.
When I completed the square, I obtained -676/15 as my constant, which is none other than -15 - 1/45. Although the actual height of the ramp is 15 m, the curve is actually a rather good fitting to the ramp as the minimum point of -15 - 1/45 is very close to a value of - 15 (with a small margin of -1/45).
For parts two and three, I rely on the curve fitting provided rather than the actual height of the ramp, especially in part three.
When I completed the square, I obtained -676/15 as my constant, which is none other than -15 - 1/45. Although the actual height of the ramp is 15 m, the curve is actually a rather good fitting to the ramp as the minimum point of -15 - 1/45 is very close to a value of - 15 (with a small margin of -1/45).
For parts two and three, I rely on the curve fitting provided rather than the actual height of the ramp, especially in part three.
Date Posted:
4 years ago
Good morning Mr Eric! Thumbs up to your great explanation. Very clear solutions as always. Thanks a lot and have a great day ahead :)
sorry if this might be a little too late but ill like to ask how did u obtain -7 1/45
O is basically the level at the top of the highest ramp.
In the main question, the ramp is supposedly 15 m tall. However, upon closer inspection, we observe that the curve modelling the lamp has a different take on this. The model “thinks” that the ramp is 15…1/45 m tall, since we obtain -15…1/45 as part of the completed square format.
Using this model, the lowest point is -15…1/45.
The second ramp is 8 m tall. Based on my assumptions in the question, I took it that the highest point of the second ramp is 8 m above this lowest point. That’s where the -7…1/45 came about.
You could well argue that the highest point should be -7 since the diagram displays the values as such. After all, the equation model is…just a model in itself, and it may not necessary be a “perfect fit” to the scenario.
In the main question, the ramp is supposedly 15 m tall. However, upon closer inspection, we observe that the curve modelling the lamp has a different take on this. The model “thinks” that the ramp is 15…1/45 m tall, since we obtain -15…1/45 as part of the completed square format.
Using this model, the lowest point is -15…1/45.
The second ramp is 8 m tall. Based on my assumptions in the question, I took it that the highest point of the second ramp is 8 m above this lowest point. That’s where the -7…1/45 came about.
You could well argue that the highest point should be -7 since the diagram displays the values as such. After all, the equation model is…just a model in itself, and it may not necessary be a “perfect fit” to the scenario.