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C2 mathematics

someone please help?

p is the centre of the circle (x-1)^2 + (y+4)^2 = 81, q is the centre of the circle (x+3)^2 +y^2 = 36. find the exact distance between the points p and q.

thanks.
Original post by kara0935
someone please help?

p is the centre of the circle (x-1)^2 + (y+4)^2 = 81, q is the centre of the circle (x+3)^2 +y^2 = 36. find the exact distance between the points p and q.

thanks.


What are the coordinates of the respective centres?

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Reply 2
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kara0935
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Original post by majmuh24
What are the coordinates of the respective centres?

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i got p = (1, -4) q= (-3,0) and then i put it into the formula and got root 32
Original post by kara0935
i got p = (1, -4) q= (-3,0) and then i put it into the formula and got root 32


Yep, looks right. You could simplify if you want, but it's all good :biggrin:

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NikolaT
15
Original post by kara0935
i got p = (1, -4) q= (-3,0) and then i put it into the formula and got root 32


What is it you need help with, you seem to have solved the question? :smile:

Root 32 could be simplified to 4 root 2.
Reply 5
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kara0935
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Original post by NikolaT
What is it you need help with, you seem to have solved the question? :smile:

Root 32 could be simplified to 4 root 2.


i solved that one but im having difficulty with : solve the equation 2log5x - log53x = 1

i got up until log5 (x/3) =1 but i dont know what to do next :s-smilie:
Original post by kara0935
i solved that one but im having difficulty with : solve the equation 2log5x - log53x = 1

i got up until log5 (x/3) =1 but i dont know what to do next :s-smilie:


Take powers to get rid of the log and then solve normally.

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kara0935
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Original post by majmuh24
Take powers to get rid of the log and then solve normally.

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how?? :s-smilie:
Original post by kara0935
how?? :s-smilie:


Log5(x)=2 means that x=5^2

Use a similar principle

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NikolaT
15
Original post by kara0935
i solved that one but im having difficulty with : solve the equation 2log5x - log53x = 1

i got up until log5 (x/3) =1 but i dont know what to do next :s-smilie:


Hmm...

2log5(x) - log5(3x) = 1 ===> log5(x^2) - log5(3x) = 1

log5(x^2/3x) = 1

5^1 = x^2/3x

Therefore 5 = x^2/3x

You should be able to solve it from there. :smile:
Reply 10
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kara0935
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Original post by majmuh24
Log5(x)=2 means that x=5^2

Use a similar principle

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so.. log5x = 1 would turn to 5^1

then.. x/3 = 5
so x = 15?
Original post by kara0935
so.. log5x = 1 would turn to 5^1

then.. x/3 = 5
so x = 15?


Yep, that's right :biggrin: Sub it back it if you want to check :tongue:

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Reply 12
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kara0935
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Original post by majmuh24
Yep, that's right :biggrin: Sub it back it if you want to check :tongue:

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thanks for helping out :smile:

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