Question

Help with these questions please? :/ I need them done really soon...

Answer 1

could you find the inverse ?

Answer 2

y= x^2+12
solve for x

Answer 3

Find the values of x that make y=15---->solve x^2+12=15--->x^2=3-->
x can be +sqrt(3) and -sqrt(3) but you have to take only the positive value for it is a constraint in the problem

Answer 4

^ nice shortcut

Answer 5

@hartnn your approach was ok too and would obtain a general expression for the inverse, however I have used the shortcut as the problem says "evaluate"

Answer 6

right :) i was just taking the easy way...

Answer 7

I don't really get it just yet..

Answer 8

you know how to find the inverse, right ?
what have u tried for this problem ?

Answer 9

I haven't tried anything yet, I don't understand how to do it
I'm not sure where Carlos got the 15 from

Answer 10

15 was in the question....

Answer 11

y= x^2+12 -- solve for x
y - 12 = x^2
\[\sqrt{y} - 3.46]
Is that right?

Answer 12

\[\sqrt{y} - 3.46\] *

Answer 13

Ah, I didn't see that he had put that part in
I'm more of a visual learner so words kind of get lost to me ><

Answer 14

y - 12 = x^2
\(x= \sqrt{y-12} \)

so your inverse is just \(\sqrt{x-12}\)
got this ?

Answer 15

and since x\(\ge 0\) we ignore \(-\sqrt{x-12}\)

Answer 16

y - 12 = x^2
\(x=\pm\sqrt{y-12}\) *****

Answer 17

Might be a stupid question, but if we ignore \[- \sqrt{x - 12}\] how come the answer is plus or minus the square root of y - 12?

Answer 18

the inverse is still just + sqrt(x-12)
ok,
y-12 = x^2
so, x = +/- sqrt {y-12}
but x is >=0 , so we ignore negative value
so, x = + sqrt {y-12}
hence the inverse is sqrt{x-12}
ok?

Answer 19

Ohh I get it, it can't be negative since it has to be either more or equal to 0 right?

Answer 20

yes!

Answer 21

now to get g^{-1} (-15) , just put x= -15 in inverse

Answer 22

sorry, it was +15
so put x=15

Answer 23

15 = + sqrt {15 - 12}
Is that it?

Answer 24

you mean g^{-1} (15) = sqrt{15-12}
??
yes, correct :)
g^{-1} (15) = sqrt{3}

Answer 25

okay I think I'm getting it, are these our steps?

y= x^2+12 -- solve for x
y - 12 = x^2
x = + sqrt {x-12}
g^{-1} (15) = sqrt{15-12}
g^{-1} (15) = sqrt{3}

Answer 26

correct :)

Answer 27

x = + sqrt {x-12} <-----just mention, since x>=0

Answer 28

the nice thing about math is once you get it, its not that complicated and make sense

Answer 29

true!
and the more you practice, the more you get it :)

Answer 30

Yup!:3 I have to do 4 more questions before I done with the practice xD I wouldn't be on here so much if my book didn't assume I was Einstein

Answer 31

lol ! good luck :)

Answer 32

Thanks! More likely than not I'll be back xD