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# sketching curves question - c1 edexcel Watch

1. Hello,

I have a quesiton. By the way this is for Core 1 for the Edexcel Board.

This is the exercise im doing.

i done question 1f and i seem to have got it right. but i dont get the hint which is mentioned in the pink box. I have no clue how it relates to 1f. on the cd it elaborates a little

"Use x=2 to see if the curve y=-1/x cuts through the portion of y=x(x-4) that is below the x-axis."

this was my sketch

(Obviously its very wonky here cause i used paint, but you get the point)

why does the cd say "Use x=2 to see if the curve y=-1/x cuts through the portion of y=x(x-4) that is below the x-axis." when quite clearly y= -1/x does cut through the portion of y=x(x-4) that is below the x-axis, so why are they going on about using x=2

im very confused, hope this made sense.

thanks
2. Using x=2 is just a check to make sure that your sketch is correct. You want to check that y=x(x-4) is below y=-1/x at this point.
3. (Original post by Phil_Waite)
Using x=2 is just a check to make sure that your sketch is correct. You want to check that y=x(x-4) is below y=-1/x at this point.
Absolutely. None of these questions are difficult tbh - just put x and y, in turn, equal to zero to find intersections with the co-ordinate axes. Then just solve them simultaneously.
4. It's just a value you can use to check your sketch is correct, probably x=2 was chosen as it's the minimum of y=x(x-4)
5. Hey I use the same book. It isnt that difficult. What you do is find x=0 and y=0. Then draw curve according to if a>0 or a<0 and b^2<4ac or b^2>4ac. I think in the same book - there is step to step instruction on how to solve it. It helped me - and awful lot. Good Luck =)
6. i get how to do it , but what i dont get it is why you "Use x=2 to see if the curve y=-1/x cuts through the portion of y=x(x-4) that is below the x-axis."

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Updated: December 5, 2010
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