Help me : Im an idiot. (1 Viewer)

kpq_sniper017

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d/dx pretty much means "find the derivative of..."

e.g. instead of writing:

y=x^2
.'. dy/dx = 2x

you can just write:
d/dx x^2 = 2x

it's just faster.
 

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different notation's for differentiation include

dy/dx
d/dx
y'

when you write something using d/dx notation be sure to put the differential eq. in brackets

eg
d/dx(x^2)
d/dx(x^3+5x+3)
 

CM_Tutor

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It's only a minor pont, but d/dx actually means "derivative with respect to x of" - it's a good idea to keep in mind with respect to which variable you are differentiating. :)
 

kpq_sniper017

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Originally posted by CM_Tutor
It's only a minor pont, but d/dx actually means "derivative with respect to x of" - it's a good idea to keep in mind with respect to which variable you are differentiating. :)

Just on that....I guess that pretty much means that something like:

d/dx (y^2) doesn't make sense then does it??

you'd actually have to put:

d/dy (y^2)=

???
 

CM_Tutor

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Actually, interpretation of d/dx(y<sup>2</sup>) depends on what y is. If y is a constant, then nike33 is correct, and it's 0. If y is a function of x, then the chain rule dictates that d/dx(y<sup>2</sup>) = d/dy(y<sup>2</sup>) * dy/dx = 2y * dy/dx - note that this is an Extn 2 level interpretation. If y is some other case... well, let's just not go there. :)
 

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