# Proportionality question

Announcements
#1
How do you do this type of question?
0
7 years ago
#2
(Original post by Peanut247)
How do you do this type of question?
Do you know how to rewrite a statement like "x is directly proportional to the square of z" in terms of indices and some unknown constant(s)?
0
#3
(Original post by davros)
Do you know how to rewrite a statement like "x is directly proportional to the square of z" in terms of indices and some unknown constant(s)?
x [directly proportional to] k(z^2)
0
7 years ago
#4
(Original post by Peanut247)
x [directly proportional to] k(z^2) 0
7 years ago
#5
(Original post by Peanut247)
x [directly proportional to] k(z^2)
Not quite - see TenOfThem's correction!

Now you should be able to write something similar for the case of inverse proportion 0
#6
(Original post by davros)
Not quite - see TenOfThem's correction!

Now you should be able to write something similar for the case of inverse proportion y=1/(z^3)
0
7 years ago
#7
(Original post by Peanut247)
y=1/(z^3) 0
7 years ago
#8
(Original post by Peanut247)
y=1/(z^3)
Again, see TenOfThem's correction - you missed out the constant!!

Now you just need to combine these things in various ways 0
#9
(Original post by davros)
Again, see TenOfThem's correction - you missed out the constant!!

Now you just need to combine these things in various ways This was the bit I got stuck on.. I tried making them both equal z but just flopped!
0
#10
Thank you :P
0
7 years ago
#11
(Original post by Peanut247)
This was the bit I got stuck on.. I tried making them both equal z but just flopped!
Try making them both 0
#12
y=k/z^3 becomes 1/y^2 = kz^6

x=kz^2 becomes x^3 = kz^6

So x^3 = 1/y^2 making the answer D?  0
7 years ago
#13
(Original post by Peanut247)
y=k/z^3 becomes 1/y^2 = k^2z^6

x=kz^2 becomes x^3 = k^3z^6

So x^3 = k/y^2 making the answer D?  But, yes, D
0
X

new posts Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

Yes (134)
66.34%
No (46)
22.77%
I didn't use it to prepare (22)
10.89%