Quick Maths Question...

Woodchuck2000

Golden Member
Jan 20, 2002
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I'm doing some holiday homework and there a couple of things I'd like to check...

Q1 is:
Find the greatest domain and the corresponding range for the function y = 1 + x + x^3
Am I missing something or are the domain and range both -infinity -> infinity? It seems too easy...


Another question asks for me to perform total differentiation on a function. Does anyone know what total differentiation is?
 

Sukhoi

Elite Member
Dec 5, 1999
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Yeah, I believe they are both - and + infinity.

In calc III with multiple variables total differentition is a small formula you use, that I can't remember. However, it doesn't sound like you are in calc III. The normal derivative of that function is 3x^2 + 1.
 

Woodchuck2000

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Jan 20, 2002
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Cheers very much for your response. It just seemed far too simple to me and I thought I was missing a trick.
I'm not sure what level Calc III goes to since I'm in the UK.

The equation I have to differentiate involves mutiple variables so I'd normally use implicit differentiation. I've never heard of total differentiation though so I'm not sure if there's another way.

would the formula give a result along of the lines of:

d/dx(f(y)) = f'(y)dy/dx

I'm a little confused :(
 

Sukhoi

Elite Member
Dec 5, 1999
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It sounds like you're doing the same stuff we are. I'd like to give you the answer on the total differentiation, but all my calc stuff is at school, so I can't get the formula for you. Do some searches on Google and see if you can find anything.
 

Sukhoi

Elite Member
Dec 5, 1999
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I just finished calc III at Illinois. Calc I is just derivatives and maybe basic integrals. Calc II is more advanced integrals and series type stuff. Calc III is 3D stuff, vectors, and multiple integrals.
 

Woodchuck2000

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Jan 20, 2002
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By the sounds of it, I've done everything in Calc III, although I can't see how vectors involve calculus...
I've just never heard of a total differential before :(
 

Haircut

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Apr 23, 2000
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Originally posted by: Woodchuck2000
I can't see how vectors involve calculus...
Just wait until you get to experience the wonderful world of divs, grads and curls. :)