Question

Just need a minor reminder about how we write the domain of a function with good old mathematical notation.

Answer 1

it is really how you write an interval
all real numbers would be either \(\mathbb{R}\) or \((-\infty, \infty)\)

Answer 2

all number greater than or equal to -1 (the domain of \(f(x)=\sqrt{x+1}\) ) would be either
\[x\geq-1\] or \([-1,\infty)\)

Answer 3

if you want to be fancy and use set builder notation, you could write
\[\{x:x\geq -1\}\]

Answer 4

Was more thinking something like this (i know this might just be wrong but still):
Df={x,y│x,y∈4xy-3y^2>0}

Answer 5

What's that, x and y a function of z?

Answer 6

Okay i just give the full task: A function f is given by f(x,y)=sqrt(4xy-3y^2). I am going to find the domain, but i wanted to start writeing the domain with mathematical notation and a bit unsure about how it look lie if it is Df={f(x)│x,y∈4xy-3y^2>0} or how it was again

Answer 7

look like*

Answer 8

Df is just the domain in my language

Answer 9

{x,y│4xy-3y^2>0} (greater than or equal to 0 is also OK)

Answer 10

x,y in R?

Answer 11

Thanks what i was looking for :)

Answer 12

{x,y in R│4xy-3y^2>0}

Answer 13

Where I come from ,this would be understood without specification.....

Answer 14

yea or we can be very annoying and write {∀x,y∈C}?

Answer 15

x,y in C is sufficient

Answer 16

Let me just think, complex square root.....

Answer 17

Yes, principal value...

Answer 18

Ok but can we then write the following: {x,y∈R│4xy-3y^2>0} i mean the ∈ just means "belong to" right?

Answer 19

Yes, or simply "in"

Answer 20

Well i say thanks. Might write a new question when i need to solve the inequality.

Answer 21

ur welcome.