Eric Nicholas K's answer to Candice's Secondary 4 A Maths Singapore question.
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Hi Candice! Here are my workings for the question. I disagree with the inequality sign of the solution for part iv.
Date Posted:
4 years ago
Thank u so much for the help once again :)
The inequality is correct. You can fold the paper all the way such that x = 0. Therefore A = 0. Which just means no triangle is formed.
Likewise, if you fold such that x = 10.5, you've just folded the paper into half and no triangle is formed.
For both cases, this means PR = QR and P = Q.
Both cases satisfy the notion of the corner touching the opposite sides of the paper just that there's no triangle.
What's for sure is that x cannot be negative. In the actual graph, values for A exist for x < 0. A is negative for those x values. Just that we do not consider them since area can never be negative.
Likewise, if you fold such that x = 10.5, you've just folded the paper into half and no triangle is formed.
For both cases, this means PR = QR and P = Q.
Both cases satisfy the notion of the corner touching the opposite sides of the paper just that there's no triangle.
What's for sure is that x cannot be negative. In the actual graph, values for A exist for x < 0. A is negative for those x values. Just that we do not consider them since area can never be negative.
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