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Maths Homework - help please ASAP watch

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    a curve has equation y=3x(sqred) +6x-7. find the equation of the tangent to the curve at the point x=1, can you please explain what to do
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    (Original post by Misshussain23)
    a curve has equation y=3x(sqred) +6x-7. find the equation of the tangent to the curve at the point x=1, can you please explain what to do
    Differentiate to get the gradient function for the curve. Hence find the gradient of the curve at x = 1. Then use either  y - y_1 = m(x - x_1) or  y = mx + c to find the equation of the tangent.
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    Is this right?



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    It's perfect except for when you go from the penultimate to the final line, you've made a silly algebra mistake :-)
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    (Original post by 16Characters....)
    It's perfect except for when you go from the penultimate to the final line, you've made a silly algebra mistake :-)
    okay thankyou, i will have amend that
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    I'm not sure how you find x and y for part a 😬 can anyone help me please


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    (Original post by Misshussain23)
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    I'm not sure how you find x and y for part a 😬 can anyone help me please


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    You can start with either one, so what do you know about one of the co-ordinates when the graph meets the x axis or the y axis?
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    (Original post by SeanFM)
    You can start with either one, so what do you know about one of the co-ordinates when the graph meets the x axis or the y axis?
    i'm not sure
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    (Original post by Misshussain23)
    i'm not sure
    We could work with a more simple example and apply the same logic to your question.

    If you had the graph  y = x - 5 and sketched that, where does that cross the x and y axis? What do you notice about one of the co-ordinates in each case?
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    (Original post by SeanFM)
    We could work with a more simple example and apply the same logic to your question.

    If you had the graph  y = x - 5 and sketched that, where does that cross the x and y axis? What do you notice about one of the co-ordinates in each case?
    One of them will be 0
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    y=f(x) so y=3x-x^3, when it crosses y axis, x=0 so sub in and get value of y

    When it crosses x axis, y=0 so sub into eqaution and get value of y
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    (Original post by Misshussain23)
    One of them will be 0
    Correct, so now you just have to think: for meeting the x axis, which one will be 0? Same for the y axis, and then find the other co-ordinates.
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    (Original post by SeanFM)
    Correct, so now you just have to think: for meeting the x axis, which one will be 0? Same for the y axis, and then find the other co-ordinates.
    okay that makes sense thankyou
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    Can you please help me understand how to do this question please with a step by step process


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    (Original post by Misshussain23)
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    Can you please help me understand how to do this question please with a step by step process


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    Question 1 or 2?
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    (Original post by Andy98)
    Question 1 or 2?
    1 please
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    (Original post by Misshussain23)
    1 please
    My first step would be to rearrange the equation so you have y on one side. You know how to do that?
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    (Original post by Andy98)
    My first step would be to rearrange the equation so you have y on one side. You know how to do that?
    no im not sure, i know you have to find m by rearraringing it to y=mx+c but im not sure how to get it
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    (Original post by Misshussain23)
    no im not sure, i know you have to find m by rearraringing it to y=mx+c but im not sure how to get it
    What do you need to do to both sides to get a positive multiple of y?
 
 
 
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