given: x proportional to y. is x proportional to x?

Question

they say that x and y are directly proportional. they ask me then if its true that x is directly proportional to x which is the same variable and I'm confused.

Answer 1

Yes it is.  If x is proportional to y, then

 

x = ky,

 

with

 

k ≠ 0.

 

Similarly, x is proportional to x, since 

 

x = 1x,

 

with

 

k = 1 ≠ 0.