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# general stationary points question Watch

1. Usually in Maths exams, for AQA, i find when it asks me to Differentiate a function then find the stationary points, in the mark scheme Im only supposed to take the positive value, e.g. X^2 = 4 so X = 2 but shouldn't I take the negative as well?
2. Check the domain of the function.
3. (Original post by SunDun111)
Usually in Maths exams, for AQA, i find when it asks me to Differentiate a function then find the stationary points, in the mark scheme Im only supposed to take the positive value, e.g. X^2 = 4 so X = 2 but shouldn't I take the negative as well?
Post the question.
4. (Original post by SunDun111)
Usually in Maths exams, for AQA, i find when it asks me to Differentiate a function then find the stationary points, in the mark scheme Im only supposed to take the positive value, e.g. X^2 = 4 so X = 2 but shouldn't I take the negative as well?
Assuming ur talking bout shape questions, u have to take the positive value of x for obvious reasons

otherwise like big E said above check da domain

gl
5. (Original post by Zacken)
Post the question.
(Original post by Goatt)
Assuming ur talking bout shape questions, u have to take the positive value of x for obvious reasons

otherwise like big E said above check da domain

gl
dm read the question wrong thought it said x^2 = 4 it says x^1/2 = 4, but if your finding the equation of the normal at a stationary point, I think for the question X = 4 and Y = 8, wouldn't the equation by Y = 8, the mark scheme says X = 4
6. (Original post by SunDun111)
dm read the question wrong thought it said x^2 = 4 it says x^1/2 = 4, but if your finding the equation of the normal at a stationary point, I think for the question X = 4 and Y = 8, wouldn't the equation by Y = 8, the mark scheme says X = 4
..
7. (Original post by SunDun111)
dm read the question wrong thought it said x^2 = 4 it says x^1/2 = 4, but if your finding the equation of the normal at a stationary point, I think for the question X = 4 and Y = 8, wouldn't the equation by Y = 8, the mark scheme says X = 4
blud we need infoooo like the function ur working with

& this point u refer to
8. (Original post by SunDun111)
dm read the question wrong thought it said x^2 = 4 it says x^1/2 = 4, but if your finding the equation of the normal at a stationary point, I think for the question X = 4 and Y = 8, wouldn't the equation by Y = 8, the mark scheme says X = 4
What paper is it gg
9. (Original post by SunDun111)
dm read the question wrong thought it said x^2 = 4 it says x^1/2 = 4, but if your finding the equation of the normal at a stationary point, I think for the question X = 4 and Y = 8, wouldn't the equation by Y = 8, the mark scheme says X = 4
What does the normal look like at a stationary point? Does it look like a vertical line or a horizontal line? What does the tangent look like?
10. (Original post by Goatt)
blud we need infoooo like the function ur working with

& this point u refer to
(Original post by Goatt)
What paper is it gg
June 2011 , C2 diff question, Q5.
11. (Original post by Zacken)
What does the normal look like at a stationary point? Does it look like a vertical line or a horizontal line? What does the tangent look like?
Verticle... Ohhhh ok so would it be X = 4 instead?
12. (Original post by SunDun111)
Verticle... Ohhhh ok so would it be X = 4 instead?
Yes.
13. (Original post by SunDun111)
June 2011 , C2 diff question, Q5.
[4,8] is the max that is right

What you need to do now is find the slope of the tangent at the point M then use the normal is perpendicular rule

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