Need help with differentiation

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Matheen1
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davros
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(Original post by Matheen1)
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What have you done so far?
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Matheen1
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(Original post by davros)
What have you done so far?
I worked out dy/dx and made it equal to zero
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username5857626
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(Original post by Matheen1)
I worked out dy/dx and made it equal to zero
You need to work out the second derivative and see what that tells you.
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Matheen1
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(Original post by Bronfenbrennerzy)
You need to work out the second derivative and see what that tells you.
I got stuck on finding dy/dx
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username5857626
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(Original post by Matheen1)
I got stuck on finding dy/dx
It's pretty straightforward, differentiate y = 2x^2 - x^1/2 with respect to x. To differentiate, you multiply the number at the front of x with the exponent and then decrease the exponent by 1.
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Parinoor
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(Original post by Matheen1)
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stationary points is when dy/dx = 0 right

so first i would differentiate the equation

then set dy/dx = 0

u should only get one answer

which is ur stationary point

that x that u found, sub in original equation to get y and there u go!
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davros
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(Original post by Parinoor)
stationary points is when dy/dx = 0 right

so first i would differentiate the equation

then set dy/dx = 0

u should only get one answer

which is ur stationary point

that x that u found, sub in original equation to get y and there u go!
That's not sufficient to prove that it's a minimum though
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IJaguar
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(Original post by Matheen1)
I worked out dy/dx and made it equal to zero
Do you know how to find the nature of a stationary point?
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macpatgh-Sheldon
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(Original post by IJaguar)
Do you know how to find the nature of a stationary point?
Check by substituting example x values just slightly above and below the point:-

If value of y is sl lower just below and sl lower just above, it is a max

If both sl higher, then min.

If both in same direction, then inflexion point.

You can work out why - I know you believe in using your brain from the bio Q a few min ago!!
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