Post by: sajib_mostofa on November 03, 2010, 09:33:51 pm
Post by: Elnino_Gerrard on November 03, 2010, 09:37:21 pm
how do u know u have to take the negative root of (x-2)2
Post by: Linkage1992 on November 03, 2010, 09:39:44 pm
You have to sub in the value for which the domain of f(x) ends, and this is at x = 2, so you get the endpoint as (2,2)
Post by: sajib_mostofa on November 03, 2010, 09:42:59 pm
Post by: sajib_mostofa on November 03, 2010, 09:44:42 pm
The equation of the graph will simply be y = x. The point (2,4) doesn't lie on this line.How do you know that (2,4) doesn't lie on the line?
You have to sub in the value for which the domain of f(x) ends, and this is at x = 2, so you get the endpoint as (2,2)
Post by: Linkage1992 on November 03, 2010, 09:45:12 pm
I dont even get how they got the rule? :(
how do u know u have to take the negative root of (x-2)2
The domain of the graph is (-infinity, 2) as you found from the previous question. This means the range of the inverse function will have to be (-infinity, 2). Thus, you have to choose the option which gives this range, and so you take the negative root, as the other option doesn't give you the required range.
Post by: Linkage1992 on November 03, 2010, 09:47:15 pm
The equation of the graph will simply be y = x. The point (2,4) doesn't lie on this line.How do you know that (2,4) doesn't lie on the line?
You have to sub in the value for which the domain of f(x) ends, and this is at x = 2, so you get the endpoint as (2,2)
The equation is y = x. 4 does not equal 2 and so that point cannot lie on the line.
Post by: Elnino_Gerrard on November 03, 2010, 09:54:09 pm
Isnt it just like f(g(x))I dont even get how they got the rule? :(
how do u know u have to take the negative root of (x-2)2
The domain of the graph is (-infinity, 2) as you found from the previous question. This means the range of the inverse function will have to be (-infinity, 2). Thus, you have to choose the option which gives this range, and so you take the negative root, as the other option doesn't give you the required range.
How do we know that its the domain of the inside function that becomes the domain of the the whole function? :|:(
Im so lost
Post by: Elnino_Gerrard on November 03, 2010, 09:54:46 pm
Post by: Souljette_93 on November 03, 2010, 09:57:09 pm
Isnt it just like f(g(x))I dont even get how they got the rule? :(
how do u know u have to take the negative root of (x-2)2
The domain of the graph is (-infinity, 2) as you found from the previous question. This means the range of the inverse function will have to be (-infinity, 2). Thus, you have to choose the option which gives this range, and so you take the negative root, as the other option doesn't give you the required range.
How do we know that its the domain of the inside function that becomes the domain of the the whole function? :|:(
Im so lost
that's the rule.