Maths Question Help - GCSE!!!
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Need some help please guys, the wife is helping our niece revise for her gcse but we are struggling to remember these equations......
q1. for the equation, y=5000x - 625 xsquared, find dy/dx?
q2. find the co-ordinates of the turning point on the graph
y=5000x - 625 xsquared
Thanks
Leigh
q1. for the equation, y=5000x - 625 xsquared, find dy/dx?
q2. find the co-ordinates of the turning point on the graph
y=5000x - 625 xsquared
Thanks
Leigh
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Need some help please guys, the wife is helping our niece revise for her gcse but we are struggling to remember these equations......
q1. for the equation, y=5000x - 625 xsquared, find dy/dx?
q2. find the co-ordinates of the turning point on the graph
y=5000x - 625 xsquared
Thanks
Leigh
q1. for the equation, y=5000x - 625 xsquared, find dy/dx?
q2. find the co-ordinates of the turning point on the graph
y=5000x - 625 xsquared
Thanks
Leigh
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y = 5000x - 625x^2
First find dy/dx = 5000-1250x
Now there are turning points when dy/dx = 0, so:
0 = 5000 - 1250x
1250x = 5000
x = 500/125 or 4
To find the y-coordinate of the turning point, put this value of x into the original function:
y = 5000x - 625x^2
= 5000(500/125) - 625 (500/125)^2
=20000 - 10000
= 10000
So there is a turning point at (4, 10000)
I'm pretty sure this is right.
Rich
First find dy/dx = 5000-1250x
Now there are turning points when dy/dx = 0, so:
0 = 5000 - 1250x
1250x = 5000
x = 500/125 or 4
To find the y-coordinate of the turning point, put this value of x into the original function:
y = 5000x - 625x^2
= 5000(500/125) - 625 (500/125)^2
=20000 - 10000
= 10000
So there is a turning point at (4, 10000)
I'm pretty sure this is right.
Rich
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y = 5000x - 625x^2
First find dy/dx = 5000-1250x
Now there are turning points when dy/dx = 0, so:
0 = 5000 - 1250x
1250x = 5000
x = 500/125 or 4
To find the y-coordinate of the turning point, put this value of x into the original function:
y = 5000x - 625x^2
= 5000(500/125) - 625 (500/125)^2
=20000 - 10000
= 10000
So there is a turning point at (4, 10000)
I'm pretty sure this is right.
Rich
First find dy/dx = 5000-1250x
Now there are turning points when dy/dx = 0, so:
0 = 5000 - 1250x
1250x = 5000
x = 500/125 or 4
To find the y-coordinate of the turning point, put this value of x into the original function:
y = 5000x - 625x^2
= 5000(500/125) - 625 (500/125)^2
=20000 - 10000
= 10000
So there is a turning point at (4, 10000)
I'm pretty sure this is right.
Rich
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We are struggling with this part
____________
y = 5000x - 625x^2
First find dy/dx = 5000-1250x
Now there are turning points when dy/dx = 0, so:
0 = 5000 - 1250x
1250x = 5000
x = 500/125 or 4
_____________
We see that you have divided both sides by x, but should it not then be
5000-625x ??
Thanks
leigh
____________
y = 5000x - 625x^2
First find dy/dx = 5000-1250x
Now there are turning points when dy/dx = 0, so:
0 = 5000 - 1250x
1250x = 5000
x = 500/125 or 4
_____________
We see that you have divided both sides by x, but should it not then be
5000-625x ??
Thanks
leigh
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Y = 5000x – 625xsquared
First dy/dx = 0
So divide both side by x
y/x = (5000x / x) – (625x2/x) = 0
cancel the x’s out
0 = 5000 – 625x
Divide all parts by 625
0/625 = (5000/625) – (625x/625)
simplify
0 = 8 – x
Plus x to both sides
X = 8
No substitute x = 8 into original equation
Y = (5000 * 8) – (625 * 8)
Y = 40000 – 5000
Y = 35000
hope this helps
First dy/dx = 0
So divide both side by x
y/x = (5000x / x) – (625x2/x) = 0
cancel the x’s out
0 = 5000 – 625x
Divide all parts by 625
0/625 = (5000/625) – (625x/625)
simplify
0 = 8 – x
Plus x to both sides
X = 8
No substitute x = 8 into original equation
Y = (5000 * 8) – (625 * 8)
Y = 40000 – 5000
Y = 35000
hope this helps
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sry forgot to square 8 on last part of equation, here it is again
Y = 5000x – 625xsquared
First dy/dx = 0
So divide both side by x
y/x = (5000x / x) – (625x2/x) = 0
cancel the x’s out
0 = 5000 – 625x
Divide all parts by 625
0/625 = (5000/625) – (625x/625)
simplify
0 = 8 – x
Plus x to both sides
X = 8
No substitute x = 8 into original equation
Y = (5000 * 8) – (625 * 8squared)
Y = 40000 – 40000
Y = 0
Y = 5000x – 625xsquared
First dy/dx = 0
So divide both side by x
y/x = (5000x / x) – (625x2/x) = 0
cancel the x’s out
0 = 5000 – 625x
Divide all parts by 625
0/625 = (5000/625) – (625x/625)
simplify
0 = 8 – x
Plus x to both sides
X = 8
No substitute x = 8 into original equation
Y = (5000 * 8) – (625 * 8squared)
Y = 40000 – 40000
Y = 0
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Y = 5000x 625xsquared
First dy/dx = 0
So divide both side by x
y/x = (5000x / x) (625x2/x) = 0
cancel the xs out
0 = 5000 625x
Divide all parts by 625
0/625 = (5000/625) (625x/625)
simplify
0 = 8 x
Plus x to both sides
X = 8
No substitute x = 8 into original equation
Y = (5000 * 8) (625 * 8)
Y = 40000 5000
Y = 35000
hope this helps
First dy/dx = 0
So divide both side by x
y/x = (5000x / x) (625x2/x) = 0
cancel the xs out
0 = 5000 625x
Divide all parts by 625
0/625 = (5000/625) (625x/625)
simplify
0 = 8 x
Plus x to both sides
X = 8
No substitute x = 8 into original equation
Y = (5000 * 8) (625 * 8)
Y = 40000 5000
Y = 35000
hope this helps
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We have sussed it out using half your answer and half sonic booms answers ![Big Grin](https://passionford.com/forum/images/smilies/icon_biggrin.gif)
No substitute x = 8 into original equation
Y = (5000 * 8) – (625 * 8)
Y = 40000 – 5000
Y = 35000
hope this helps
You forgot to square the 625 8x ^2
so
40000 - 625 x 64 =y
y = 40000 - 40000 =0
So are we correct in saying
x = 8
y = 0
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No substitute x = 8 into original equation
Y = (5000 * 8) – (625 * 8)
Y = 40000 – 5000
Y = 35000
hope this helps
You forgot to square the 625 8x ^2
so
40000 - 625 x 64 =y
y = 40000 - 40000 =0
So are we correct in saying
x = 8
y = 0
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many thanks for the help guys ![Big Grin](https://passionford.com/forum/images/smilies/icon_biggrin.gif)
She is on her way home but is back tomorrow night as we have helped her so much![Surprised](https://passionford.com/forum/images/smilies/bigcry.gif)
Stand by for the next installment tomorrow![Top](https://passionford.com/forum/images/smilies/smile011.gif)
Thanks
Leigh
![Big Grin](https://passionford.com/forum/images/smilies/icon_biggrin.gif)
She is on her way home but is back tomorrow night as we have helped her so much
![Surprised](https://passionford.com/forum/images/smilies/bigcry.gif)
Stand by for the next installment tomorrow
![Top](https://passionford.com/forum/images/smilies/smile011.gif)
Thanks
Leigh
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We are struggling with this part
____________
y = 5000x - 625x^2
First find dy/dx = 5000-1250x
Now there are turning points when dy/dx = 0, so:
0 = 5000 - 1250x
1250x = 5000
x = 500/125 or 4
_____________
We see that you have divided both sides by x, but should it not then be
5000-625x ??
Thanks
leigh
____________
y = 5000x - 625x^2
First find dy/dx = 5000-1250x
Now there are turning points when dy/dx = 0, so:
0 = 5000 - 1250x
1250x = 5000
x = 500/125 or 4
_____________
We see that you have divided both sides by x, but should it not then be
5000-625x ??
Thanks
leigh
5000 - 625^2, ie 5000 - 1250