「HELP!」When asked to "explain"? (1 Viewer)

[a1079atw]

Hi guys,


I'm just wondering for (b), how should I answer it? I did this:
f(-1)= -(3/-1)=3
f(2)= -(3/2)=-3/2
but that isn't answering the question (which is, "why?") isn't it?

Thanks!

 

[Trebla]

Hi guys,

View attachment 27913
I'm just wondering for (b), how should I answer it? I did this:
f(-1)= -(3/-1)=3
f(2)= -(3/2)=-3/2
but that isn't answering the question (which is, "why?") isn't it?

Thanks!

If a function is continuous and increasing then if x₁ > x₂ then f(x₁) > f(x₂) (draw a picture if this isn't obvious). In this case, it appears that a contradiction is occuring because 2 > -1 yet f(2) < f(-1). The answer is because the function isn't continuous at x = 0. Hence, it doesn't make sense to compare the points x = 2 and x = -1 to confirm that the function is increasing because they are on different branches of the hyperbola.

 

[a1079atw]

If a function is continuous and increasing then if x₁ > x₂ then f(x₁) > f(x₂) (draw a picture if this isn't obvious). In this case, it appears that a contradiction is occuring because 2 > -1 yet f(2) < f(-1). The answer is because the function isn't continuous at x = 0. Hence, it doesn't make sense to compare the points x = 2 and x = -1 to confirm that the function is increasing because they are on different branches of the hyperbola.

Got it, thx!!