• Support PF! Buy your school textbooks, materials and every day products Here!

Plotting Two Variables

  • Thread starter Peter G.
  • Start date
  • #1
442
0
Hi,

The question is the following:

Another student proposes that c is proportional to d0.5 State a suitable graph that can be plotted to test this proposal.

I suggested plotting log c = 0.5 log d.

One of the answers the markscheme accepts is log c = log d

Can anyone tell me why my answer is wrong?

Thanks!
 

Answers and Replies

  • #2
785
15
Hi,

The question is the following:

Another student proposes that c is proportional to d0.5 State a suitable graph that can be plotted to test this proposal.
Inversely proportional or directly proportional ?

I suggested plotting log c = 0.5 log d.

One of the answers the mark scheme accepts is log c = log d

Can anyone tell me why my answer is wrong?

Thanks!
Is c directly proportional to d1/2 ? If so , then equation cannot be log c = 0.5 log d.

Anyways what's precisely is question asking for ? Your answer seems to be wrong because you missed the constants involved in proportionality.
 
  • #3
442
0
It is supposed to be directly proportional I guess, since they want a straight line through the origin.

I just don't understand how you can get lg c = lg d like the mark scheme asks for
 
  • #4
Redbelly98
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
12,100
129
I just don't understand how you can get lg c = lg d like the mark scheme asks for
The mark scheme appears to be wrong. Perhaps the person who wrote it accidentally left out the 0.5 factor.
 

Related Threads on Plotting Two Variables

Replies
10
Views
1K
  • Last Post
Replies
12
Views
470
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
19
Views
1K
  • Last Post
Replies
6
Views
7K
  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
19
Views
2K
  • Last Post
Replies
11
Views
572
  • Last Post
Replies
2
Views
2K
Top