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C1 Indices help?

Can anyone see why this method hasnt worked? The answer is 2/5x^2


​Thanks!
Indices Problem.pdf127.2KB
Original post by Tommehh
Can anyone see why this method hasnt worked? The answer is 2/5x^2


​Thanks!

Have you used 4 in both part 1 and in part 2?
You've used the 4 on the denominator twice.
Reply 3
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Tommehh
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Original post by maggiehodgson
Have you used 4 in both part 1 and in part 2?


Hey,

I've only used the power 4 for part 2, i used the 4 in part 1 because its all getting divided by 4.
When you split the fraction into two parts, you left the denominator as 4 for both of them, which you can only do if the numerator is an addition or subtraction (e.g. (4-2x)/4). If you're splitting up multiplied values, the denominator needs to be split into values that multiply to 4. Try doing each part again but over 2 instead of over 4.

(or you could just use 4 for 1 of them and not the other)
you wrote 2/x2 :naughty:
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Tommehh
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Original post by rayquaza17
You've used the 4 on the denominator twice.


Cant 25X4 / 4, Be written as 25/4 and x4/4 and then times together? Thanks!
Original post by Tommehh
Cant 25X4 / 4, Be written as 25/4 and x4/4 and then times together? Thanks!


No, because when multiplying fractions, you multiply the denominators together too, and this would give you a denominator of 16.
Original post by Tommehh
Hey,

I've only used the power 4 for part 2, i used the 4 in part 1 because its all getting divided by 4.



As far as I can see you've done this (25/4)^-0.5 X (x^4/4)^-0.5, haven't you?
Reply 9
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Tommehh
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Original post by lukejoshjames
When you split the fraction into two parts, you left the denominator as 4 for both of them, which you can only do if the numerator is an addition or subtraction (e.g. (4-2x)/4). If you're splitting up multiplied values, the denominator needs to be split into values that multiply to 4. Try doing each part again but over 2 instead of over 4.

(or you could just use 4 for 1 of them and not the other)


Thanks i didnt realise that! i got Root 2 x Root 2 to give the 2 on the numerator which is right ,so thanks for the explanation :smile:
Original post by Tommehh
Thanks i didnt realise that! i got Root 2 x Root 2 to give the 2 on the numerator which is right ,so thanks for the explanation :smile:


No problem! :smile:
Also, it's probably better to just put one of the parts over 4, and not split it into 2 for each part (e.g. if the fraction was (5x^2)/4 it's better to split it into 5/4 and x^2 than 5/2 and (x^2)/2), as for more complicated problems it might not be so simple.
Reply 11
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Tommehh
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Original post by lukejoshjames
No problem! :smile:
Also, it's probably better to just put one of the parts over 4, and not split it into 2 for each part (e.g. if the fraction was (5x^2)/4 it's better to split it into 5/4 and x^2 than 5/2 and (x^2)/2), as for more complicated problems it might not be so simple.


Right okay ill be sure to remember that for my upcoming exams, thanks for all your help! have a good easter!
Original post by Tommehh
Right okay ill be sure to remember that for my upcoming exams, thanks for all your help! have a good easter!

Thanks, you too :biggrin:

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