A level Pure help | Revision Server | Page 1

zealous dome Jan 8, 2023, 4:04 PM

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I need help on part C

pliant solar Jan 8, 2023, 4:09 PM

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yk for b

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did you set the curve and the line l equal to each other and got that equation

modest rapids Jan 8, 2023, 4:17 PM

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discriminant

b^2-4ac = 0

wicked crag Jan 8, 2023, 4:36 PM

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So for c u do simultaneous equations with the curve and straight line and as it says tangent means 1 point of intersection so b²-4ac=0 so then u use that to find the values of k

zealous dome Jan 8, 2023, 5:34 PM

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pliant solar did you set the curve and the line l equal to each other and got that equation

yeah ive done that

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so i just do b^2-4ac = 0

pliant solar Jan 8, 2023, 5:34 PM

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yeah so then do disc

zealous dome Jan 8, 2023, 5:34 PM

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in terms of k

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ok

pliant solar Jan 8, 2023, 5:34 PM

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yh

zealous dome Jan 8, 2023, 5:34 PM

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thanks

pliant solar Jan 8, 2023, 5:34 PM

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np

zealous dome Jan 8, 2023, 5:37 PM

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@pliant solar Ive done the question but why do i use b^2 - 4ac = 0 and not the others like >0 etc

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what in the question gives it away

pliant solar Jan 8, 2023, 5:37 PM

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because it wants values of k for which l is a tangent

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meaning it touches at one point

zealous dome Jan 8, 2023, 5:37 PM

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ah yeah i remember now

pliant solar Jan 8, 2023, 5:37 PM

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thats why the q says exact values

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and not set of values

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