Post by: bully3000 on April 10, 2013, 01:44:29 pm
(a) Evaluate
(b) Find all
Any help will be appreciated!
Post by: Jaswinder on April 10, 2013, 01:59:43 pm
a)5, -1, -8, -5
b)-0.5 and 4
Post by: bully3000 on April 10, 2013, 02:14:16 pm
just checking my answers?
a)5, -1, -8, -5
b)-0.5 and 4
I don't know what the answers are. SORRY!
Post by: Zealous on April 10, 2013, 04:14:36 pm
just checking my answers?Yep, looks like your answers seem correct, I haven't actually come across questions exactly like this, but I can assume you answer it like this.
a)5, -1, -8, -5
b)-0.5 and 4
For
So I'll just show you a and d, you can try do b and c yourself.
a)
=
Then sub in x = -2
=
=
d)
Since we are looking at subbing in x when it is 2 (which is > 0), we use the bottom part of the hybrid function.
(
Then you can sub in 2.
= (
= (
=
If you want me to write out how to do the 2nd part of the question step by step, I can do that later, you just have to equate the equations and solve for x, but you have to take into consideration the hybrid function.
I might have made errors there... someone else can correct me if I've made mistakes.
Post by: Zealous on April 10, 2013, 07:28:47 pm
(if you haven't tried and figured it out already.)
Spoiler
You need to find the intersection points of 
and 
when x is greater or equal to 0 and the intersection points of 
and 
when x is less than 0.
Note this is how I approached this question, there may be other ways.
Equate the first two:
Then solve for x
(x-4) = 0)
or 
But as we are looking at when x is greater than 0, we cannot have a solution of -1.
So the first solution is
Now we can equate the other two equations:
So the two solkutions are and 
Note this is how I approached this question, there may be other ways.
Equate the first two:
Then solve for x
But as we are looking at when x is greater than 0, we cannot have a solution of -1.
So the first solution is
Now we can equate the other two equations:
So the two solkutions are
Post by: bully3000 on April 12, 2013, 10:52:53 am
Yep, looks like your answers seem correct, I haven't actually come across questions exactly like this, but I can assume you answer it like this.
For, it's just like saying
and then subbing in
in the place of
. Since we know
is going to be
, we use the bottom part of the hybrid function (because we are subbing in -2 so we see which part of the hybrid function defines x when it is < 0.
So I'll just show you a and d, you can try do b and c yourself.
a)
=
Then sub in x = -2
=
=
d))
Since we are looking at subbing in x when it is 2 (which is > 0), we use the bottom part of the hybrid function.
()
Then you can sub in 2.
= ()
= ()
=
If you want me to write out how to do the 2nd part of the question step by step, I can do that later, you just have to equate the equations and solve for x, but you have to take into consideration the hybrid function.
I might have made errors there... someone else can correct me if I've made mistakes.
Couldn't check answers with cas calculator... :(
Post by: bully3000 on April 12, 2013, 12:34:41 pm
Yep, looks like your answers seem correct, I haven't actually come across questions exactly like this, but I can assume you answer it like this.
For
So I'll just show you a and d, you can try do b and c yourself.
a)
=
Then sub in x = -2
=
=
d)
Since we are looking at subbing in x when it is 2 (which is > 0), we use the bottom part of the hybrid function.
(
Then you can sub in 2.
= (
= (
=
If you want me to write out how to do the 2nd part of the question step by step, I can do that later, you just have to equate the equations and solve for x, but you have to take into consideration the hybrid function.
I might have made errors there... someone else can correct me if I've made mistakes.
For the rest of question a) are these, right?
Substituting x=-1
Substituting x=1
Post by: bully3000 on April 12, 2013, 12:35:53 pm