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Differentaitin help

Please can someone help, ive tried to do this so many times

1)find the x coordinate of the point on the curve y= (x^3)/3 - 3x^2 + 2/3 where the tangent is parallel to the tangent drawn at point (1,2)

thank you :smile:
Original post by slothgal
Please can someone help, ive tried to do this so many times

1)find the x coordinate of the point on the curve y= (x^3)/3 - 3x^2 + 2/3 where the tangent is parallel to the tangent drawn at point (1,2)

thank you :smile:


The point (1,2) isn't on the curve. Is that intentional, or should it be (1,-2) ?
Reply 2
yes sorry it should be (1,-2), thanks
Reply 3
bump please help
Reply 4
Original post by slothgal
bump please help


unpick the question

You want 2 parallel lines

You will need their gradient

How will you find the gradient of the tangent to the curve at (1, -2)
Reply 5
parallel lines have the same gradient, so it has the same gradient as the curve?
Reply 6
Original post by slothgal
parallel lines have the same gradient, so it has the same gradient as the curve?


yes
Reply 7
thank you, ill try to work it out now :smile:
Reply 8
sorry how can i differentiate (x^3)/3
Reply 9
Original post by slothgal
sorry how can i differentiate (x^3)/3


How would you usually differentiate axnax^n
Reply 10
x^3 is 3x^2
Original post by slothgal
x^3 is 3x^2


x33x2x^3 \neq 3x^2

What you're trying to say is that the first derivative of x3x^3 with respect to xx is 3x23x^2.
Original post by slothgal
x^3 is 3x^2


yep

So if you divide that by 3 you will get ... ...
Reply 13
X^2! Thank you, im a fool
Original post by slothgal
X^2! Thank you, im a fool


less of a fool if you use the quote facility so that I can see you have responded :smile:

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