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Integration help needed?!?

3/4x^2 - 5(sqrt)x+2/(sqrt)x


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Reply 1
Original post by benn9
3/4x^2 - 5(sqrt)x+2/(sqrt)x


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If you write each term in standard index form i.e. kxnkx^n for some values of k and n then you should just be able to apply standard integration rules for powers of x. What have you tried so far?
Original post by davros
If you write each term in standard index form i.e. kxnkx^n for some values of k and n then you should just be able to apply standard integration rules for powers of x. What have you tried so far?


You don't mean standard index form do you? You just melted the brains of several TSR users.
Reply 3
I have no idea how to do this question :frown:


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Reply 4
Original post by benn9
I have no idea how to do this question :frown:


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Can you intergrate stuff like x^2, x^-2 and x^3/2?

Do you know your rules of indices?

If yes, you should be able to do these questions.

Here's a start:

3/4x^2=3/4(1/x^2)=(3x^-2)/4

5rootx=5x^1/2

You need to combine these two ideas to get the last ones in index form. In order to integrate fractions with x's on the bottom or roots of x you need to first express them in index form, like what's in bold.

I suggest watching this video:

http://www.examsolutions.net/maths-revision/core-maths/integration/methods/ax^n/tutorial-2.php

(Paste it into your search engine)
(edited 10 years ago)
Reply 5
Original post by Mr M
You don't mean standard index form do you? You just melted the brains of several TSR users.


I just meant in the ordinary sense of writing the expressions in the explicit form kxnkx^n with a coefficient multiplying x raised to the power of an index, rather than the (possibly less clear) division by a power of x or by a radical/surd expression - I wasn't intending "standard index form" as a precise technical description!

What do you use "standard index form" to mean? (It's not a phrase I ever have reason to use to be honest - is it what we used to call "scientific notation" like 1.5×1081.5 \times 10^8?)
Original post by davros
What do you use "standard index form" to mean? (It's not a phrase I ever have reason to use to be honest - is it what we used to call "scientific notation" like 1.5×1081.5 \times 10^8?)


Yes.

http://www.bbc.co.uk/schools/gcsebitesize/maths/number/powersrootshirev1.shtml
Reply 7


Fair enough - let's hope no GCSE students were watching when I posted :smile:

Do I have to refer to "minus 1" as "negative 1" or was that just an urban myth?
Original post by davros
Fair enough - let's hope no GCSE students were watching when I posted :smile:

Do I have to refer to "minus 1" as "negative 1" or was that just an urban myth?


I use both interchangeably to prevent confusion in everyday life.
Reply 9
Thanks to liamnut's help I got the a right! Thank you :biggrin:


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Reply 10
*question ( put q but it autocorrected to a :tongue: )


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