Horizontal stretches/compression?

Question

For horizontal compressions, I know you do it if x is greater than 1, but do you divide or multiply the x value by the c value? Why would it be a vertical compression of c?

 

So if you had f(x)=2x, what would you do with the 2 and the x values?

 

For horizontal stretches (0<x<1), I basically have the same question. What would you do as far as the c and the x values? Why would it be a vertical compression by c?

 

So if you had f(x)=1/2x, what would you do with the 1/2 and the x values?

 

Basically, if you could explain the first answer given and why that would work, that'd be great. Thank you!

 

 

Answer 1

In general, for f(x) = cx, (c > 1), you can treat it either as horizontal compression by a factor of c, or as vertical stretch by a factor of c.

 

 If c < 1, then you treat it as horizontal stretch by a factor of c, or vertical compression by a factor of c.