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Differentiation

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Original post by _Xenon_
Is the other one negative? So (-2,-8)


yes
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_Xenon_
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Original post by Zacken
Yep! Well done. :biggrin:


Thanks so is the 2 really + or - 2 then the 2 coordinates are positive (2,8) and negative (-2,-8)
Reply 62
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_Xenon_
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Original post by samb1234
yes


Thanks ^
Reply 63
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Zacken
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Original post by _Xenon_
Thanks so is the 2 really + or - 2 then the 2 coordinates are positive (2,8) and negative (-2,-8)


Basically, you had the equation x2=4x^2 = 4 which has solutions x=±2x = \pm 2. The corresponding y-values are (2)^3 = 8 and (-2)^3 = -8.

Hence one point is (2,8)(2, 8) and the other is (−2,−8)(-2, -8). (i.e: there are two points with the same gradient) Does that answer your question? I'm not sure what you're asking.
multiply by the power and reduce the power by 1
Reply 65
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Zacken
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Original post by thefatone
multiply by the power and reduce the power by 1


...dude, what?
Original post by Zacken
...dude, what?


dydx=n×axn−1\dfrac{\mathrm d y}{\mathrm d x} = n\times ax^{n-1}
The way I learnt it was basically you multiply the multiplier of X by the power and take 1 away from the power. If there is no power then the X completely cancels out, and if there is no X, then the number completely cancels out, so 2X^3= 6X^2, x^2= 2X, -8X= -8, and 3 cancels out.
This means that dy/dx=6X^2+2X-8
I don't really get why it works, I just know that's what you do XD
Reply 68
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_Xenon_
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Original post by thefatone
multiply by the power and reduce the power by 1


Yes I understood that bit already I'm now trying harder examples
Reply 69
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_Xenon_
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Original post by Zacken
Basically, you had the equation x2=4x^2 = 4 which has solutions x=±2x = \pm 2. The corresponding y-values are (2)^3 = 8 and (-2)^3 = -8.

Hence one point is (2,8)(2, 8) and the other is (−2,−8)(-2, -8). (i.e: there are two points with the same gradient) Does that answer your question? I'm not sure what you're asking.


Hi yes that makes sense! :smile:
Original post by _Xenon_
Yes I understood that bit already I'm now trying harder examples


oh ok what about this one?

y=12x32y= \dfrac{1}{2}x^{\frac{3}{2}}
Reply 71
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Zacken
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Original post by _Xenon_
Hi yes that makes sense! :smile:


Awesome. :biggrin:
Reply 72
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_Xenon_
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Original post by thefatone
oh ok what about this one?

y=12x32y= \dfrac{1}{2}x^{\frac{3}{2}}


No I don't know fractions one please explain it. :-)
EDIT: I don't think I need to know that type for my exam, not sure.
Original post by _Xenon_
No I don't know fractions one please explain it. :-)
EDIT: I don't think I need to know that type for my exam, not sure.


Its exactly the same process
Original post by _Xenon_
No I don't know fractions one please explain it. :-)
EDIT: I don't think I need to know that type for my exam, not sure.


oh

multiply 12 by 32 then reduce the power by 1 \frac{1}{2}\ by\ \frac{3}{2}\ then\ reduce\ the\ power\ by\ 1
Reply 75
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_Xenon_
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Original post by samb1234
Its exactly the same process


oK thanks I'll now answer the questions in my exam practise book.
Then I need to do some Chemistry revision
Reply 76
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Zacken
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Original post by _Xenon_
oK thanks I'll now answer the questions in my exam practise book.
Then I need to do some Chemistry revision


Hey! I'd just like to say that you've done really well in learning this differentiation thing so far, good job! :smile:
Reply 77
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_Xenon_
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Original post by Zacken
Hey! I'd just like to say that you've done really well in learning this differentiation thing so far, good job! :smile:


Thanks I think my teacher didn't teach these topics because they want the class to achieve Cs to at least pass maths and maybe some students would have struggled but I can do much better than that so I'm trying to learn these extra topics myself for maximum marks. Thanks very much for helping me with this otherwise I wouldn't have understood. I really appreciate it. :smile::smile:

I have an exam practise book with exam style questions for every topic on my exam so I'm just trying to learn what I don't know atm. Thanks again!
Original post by _Xenon_
oK thanks I'll now answer the questions in my exam practise book.
Then I need to do some Chemistry revision


Have fun - I'm doing chem revision atm lol
Reply 79
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Notnek
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Original post by _Xenon_
Thanks I think my teacher didn't teach these topics because they want the class to achieve Cs to at least pass maths and maybe some students would have struggled but I can do much better than that so I'm trying to learn these extra topics myself for maximum marks.

What grade are you aiming for?

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