Question

I need someone to walk me through a couple of problems. The first is f(x)= lxl+1find the domain algebraically.

Answer 1

unless otherwise specified the domain will be all real numbers, since you can take the absolute value of anything

Answer 2

I agree with satellite's diagnosis.

Answer 3

the real truth is that you should specify the domain of the function when you define it, but if you don't it is assumed to be the largest set of numbers on which the function can act, so in this case anything

Answer 4

I need to show algebra for credit

Answer 5

sorry but there is no algebra to do here

Answer 6

There is no algebra to show.

Answer 7

math is not about algebra, math is about reasoning

Answer 8

ok how about 2x^3-5x+6

Answer 9

It is a polynomial. Those things exist for any input x which means its domain is all read numbers

Answer 10

polynomial domain is still all real numbers. you only have to worry about division by zero, or taking a even root of a negative number. both of those are not allowed, but most things are permitted

Answer 11

The instructions are to find the domain algebraically. You set the function =0 and solve. I am not sure how to do this on these problems.

Answer 12

again, no algebra to show

Answer 13

Are you sure it says find domain and not x-intercepts?

Answer 14

setting the function = 0 tells you where it is zero, not what the domain is

Answer 15

yes I am sure and I realize that this tells me the zero but it is what I have to do in order to get credit. Going through and stating only domain with no work gets me nothing. I have to find the zero.

Answer 16

Finding the zero is not equivalent to finding the domain

Answer 17

those are separate problems and are unrelated

Answer 18

I understand what you all are saying. I am saying I have to find the zero to get credit for work. Would it help if I asked you to show me how to find the zero for these?

Answer 19

You could say that |x| >=0 for all real numbers so the domain is all real numbers.

Answer 20

There is no zero for f(x)=|x|+1

Answer 21

because |x| can never = -1

Answer 22

\[|x|+1\geq 1\] so it is never zero

Answer 23

what about 2x^3-5x+6?

Answer 24

So we can try syntehtic division to find rational solutions but this does not guarantee there are rational solutions

Answer 25

Did you perhaps say domain when you meant range?

Answer 26

No, I need to find the zero

Answer 27

i be right back
using synthetic division and trail and error and finding zeros I found one zero to be x=-2