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Hi I was wondering if anyone would be able to help me with a homework question:
P, Q and R have positive values.
P is directly proportional to the square of Q.
When P = 1.25, Q = 0.5
Q is inversely proportional to R.
When Q = 0.5, R = 6
Work out the value of R when P = 0.8
It’s probably really easy but idk where to start
Thanks in advance
P, Q and R have positive values.
P is directly proportional to the square of Q.
When P = 1.25, Q = 0.5
Q is inversely proportional to R.
When Q = 0.5, R = 6
Work out the value of R when P = 0.8
It’s probably really easy but idk where to start
Thanks in advance
Last edited by 67824930; 1 month ago
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#2
Edit
orry wrong post
Did you change your question??
orry wrong postDid you change your question??
Last edited by GabiAbi84; 1 month ago
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#4
(Original post by 67824930)
Hi I was wondering if anyone would be able to help me with a homework question:
P, Q and R have positive values.
P is directly proportional to the square of Q.
When P = 1.25, Q = 0.5
Q is inversely proportional to R.
When Q = 0.5, R = 6
Work out the value of R when P = 0.8
It’s probably really easy but idk where to start
Thanks in advance
Hi I was wondering if anyone would be able to help me with a homework question:
P, Q and R have positive values.
P is directly proportional to the square of Q.
When P = 1.25, Q = 0.5
Q is inversely proportional to R.
When Q = 0.5, R = 6
Work out the value of R when P = 0.8
It’s probably really easy but idk where to start
Thanks in advance
Last edited by GabiAbi84; 1 month ago
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(Original post by GabiAbi84)
So when something is directly proportional how can we write that in an equation?
So when something is directly proportional how can we write that in an equation?
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#6
(Original post by 67824930)
I think it’s y = kx but I don’t really understand what the k means
I think it’s y = kx but I don’t really understand what the k means
So you know that P is directly proportional to the square of Q -how would you write that?
Last edited by GabiAbi84; 1 month ago
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(Original post by GabiAbi84)
K is a constant -a multiplier that shows the relationship between the two values.
So you know that P is directly proportional to the square of Q -how would you write that?
K is a constant -a multiplier that shows the relationship between the two values.
So you know that P is directly proportional to the square of Q -how would you write that?
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#8
(Original post by 67824930)
P = kQ² ? Idk
P = kQ² ? Idk
Now use the values they give you
“When P=1.25, Q=0.5”
and put them into that equation to work out the value of k
Last edited by GabiAbi84; 1 month ago
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(Original post by GabiAbi84)
Yup that’s it.
Now use the values they give you
“When P=1.25, Q=0.5”
and put them into that equation to work out the value of k
Yup that’s it.
Now use the values they give you
“When P=1.25, Q=0.5”
and put them into that equation to work out the value of k
1.25 / 0.25 = 5
K = 5 ?
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#10
Now how do we write when something is inversely proportional?
Last edited by GabiAbi84; 1 month ago
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(Original post by GabiAbi84)
👍🏼 now you can rewrite your formula for p and q using that value for k.
Now how do we write when something is inversely proportional?
👍🏼 now you can rewrite your formula for p and q using that value for k.
Now how do we write when something is inversely proportional?
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#12
(Original post by 67824930)
y = k / x
y = k / x
Once you’ve written that equation, sub in the value the question gives you to find out k for this one.
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(Original post by GabiAbi84)
Excellent, now the question tells you that Q is inversely proportional to R.
Once you’ve written that equation, sub in the value the question gives you to find out k for this one.
Excellent, now the question tells you that Q is inversely proportional to R.
Once you’ve written that equation, sub in the value the question gives you to find out k for this one.
k = 3
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#14
One connecting P and Q and the other connecting Q and R
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(Original post by GabiAbi84)
Fab so you should now have two equations
One connecting P and Q and the other connecting Q and R
Fab so you should now have two equations
One connecting P and Q and the other connecting Q and R
P = 5Q²
Q = 3 / R
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(Original post by GabiAbi84)
Why do you think it’s wrong?
Why do you think it’s wrong?
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#18
(Original post by 67824930)
I’m not sure it was just a guess
I’m not sure it was just a guess
you worked out k and then you put those values back into the equations for proportional relations. Now you have those two equations, can you finish off the question?
Last edited by GabiAbi84; 1 month ago
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(Original post by gabiabi84)
well it’s correct you worked out k and then you put those values back into the equations for proportional relations.
now you have those two equations, can you finish off the question?
well it’s correct
you worked out k and then you put those values back into the equations for proportional relations. now you have those two equations, can you finish off the question?
q = 0.4
0.4 = 3 / r
r = 7.5 ?
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