Domain of $f(x)$ is $[-1,2]$; find domain of $f([x]-x^2+4)$ [closed]
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The question goes like this
Domain of f(x) is [-1,2] find domain of f([x]-x²+4) [•] is greatest integer function.
I know that I have to do this
$-1leq [x]-x^2+4leq 2$
But what to do next. I can't even factorise it.
algebra-precalculus functions
closed as off-topic by amWhy, José Carlos Santos, Chris Custer, Leucippus, Parcly Taxel Jul 26 at 1:10
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – amWhy, José Carlos Santos, Chris Custer, Leucippus, Parcly Taxel
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up vote
-1
down vote
favorite
The question goes like this
Domain of f(x) is [-1,2] find domain of f([x]-x²+4) [•] is greatest integer function.
I know that I have to do this
$-1leq [x]-x^2+4leq 2$
But what to do next. I can't even factorise it.
algebra-precalculus functions
closed as off-topic by amWhy, José Carlos Santos, Chris Custer, Leucippus, Parcly Taxel Jul 26 at 1:10
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – amWhy, José Carlos Santos, Chris Custer, Leucippus, Parcly Taxel
add a comment |Â
up vote
-1
down vote
favorite
up vote
-1
down vote
favorite
The question goes like this
Domain of f(x) is [-1,2] find domain of f([x]-x²+4) [•] is greatest integer function.
I know that I have to do this
$-1leq [x]-x^2+4leq 2$
But what to do next. I can't even factorise it.
algebra-precalculus functions
The question goes like this
Domain of f(x) is [-1,2] find domain of f([x]-x²+4) [•] is greatest integer function.
I know that I have to do this
$-1leq [x]-x^2+4leq 2$
But what to do next. I can't even factorise it.
algebra-precalculus functions
edited Jul 25 at 21:40


amWhy
189k25219431
189k25219431
asked Jul 25 at 6:05
user199925
194
194
closed as off-topic by amWhy, José Carlos Santos, Chris Custer, Leucippus, Parcly Taxel Jul 26 at 1:10
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – amWhy, José Carlos Santos, Chris Custer, Leucippus, Parcly Taxel
closed as off-topic by amWhy, José Carlos Santos, Chris Custer, Leucippus, Parcly Taxel Jul 26 at 1:10
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – amWhy, José Carlos Santos, Chris Custer, Leucippus, Parcly Taxel
add a comment |Â
add a comment |Â
1 Answer
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Let $n le x <n+1$. It is easy to see that for $|n| ge 3, [x]-x^2+4 <-1$.
Hence you have consider only the values $n=-2,-1,0,1,2$. Now try to solve the inequalities for these cases.
1
We are defining $n = [x]$ (that is what $n le x < n+1$ says). $x$ cannot be 2.8 or 2.9 if $|n| ge 3$.
– Ted
Jul 25 at 7:15
Sorry guys for the trouble. I m really a blockhead. Now I understand everything that he wrote.
– user199925
Jul 25 at 13:34
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1 Answer
1
active
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
Let $n le x <n+1$. It is easy to see that for $|n| ge 3, [x]-x^2+4 <-1$.
Hence you have consider only the values $n=-2,-1,0,1,2$. Now try to solve the inequalities for these cases.
1
We are defining $n = [x]$ (that is what $n le x < n+1$ says). $x$ cannot be 2.8 or 2.9 if $|n| ge 3$.
– Ted
Jul 25 at 7:15
Sorry guys for the trouble. I m really a blockhead. Now I understand everything that he wrote.
– user199925
Jul 25 at 13:34
add a comment |Â
up vote
2
down vote
Let $n le x <n+1$. It is easy to see that for $|n| ge 3, [x]-x^2+4 <-1$.
Hence you have consider only the values $n=-2,-1,0,1,2$. Now try to solve the inequalities for these cases.
1
We are defining $n = [x]$ (that is what $n le x < n+1$ says). $x$ cannot be 2.8 or 2.9 if $|n| ge 3$.
– Ted
Jul 25 at 7:15
Sorry guys for the trouble. I m really a blockhead. Now I understand everything that he wrote.
– user199925
Jul 25 at 13:34
add a comment |Â
up vote
2
down vote
up vote
2
down vote
Let $n le x <n+1$. It is easy to see that for $|n| ge 3, [x]-x^2+4 <-1$.
Hence you have consider only the values $n=-2,-1,0,1,2$. Now try to solve the inequalities for these cases.
Let $n le x <n+1$. It is easy to see that for $|n| ge 3, [x]-x^2+4 <-1$.
Hence you have consider only the values $n=-2,-1,0,1,2$. Now try to solve the inequalities for these cases.
edited Jul 25 at 21:41


amWhy
189k25219431
189k25219431
answered Jul 25 at 6:29


Kavi Rama Murthy
20.1k2829
20.1k2829
1
We are defining $n = [x]$ (that is what $n le x < n+1$ says). $x$ cannot be 2.8 or 2.9 if $|n| ge 3$.
– Ted
Jul 25 at 7:15
Sorry guys for the trouble. I m really a blockhead. Now I understand everything that he wrote.
– user199925
Jul 25 at 13:34
add a comment |Â
1
We are defining $n = [x]$ (that is what $n le x < n+1$ says). $x$ cannot be 2.8 or 2.9 if $|n| ge 3$.
– Ted
Jul 25 at 7:15
Sorry guys for the trouble. I m really a blockhead. Now I understand everything that he wrote.
– user199925
Jul 25 at 13:34
1
1
We are defining $n = [x]$ (that is what $n le x < n+1$ says). $x$ cannot be 2.8 or 2.9 if $|n| ge 3$.
– Ted
Jul 25 at 7:15
We are defining $n = [x]$ (that is what $n le x < n+1$ says). $x$ cannot be 2.8 or 2.9 if $|n| ge 3$.
– Ted
Jul 25 at 7:15
Sorry guys for the trouble. I m really a blockhead. Now I understand everything that he wrote.
– user199925
Jul 25 at 13:34
Sorry guys for the trouble. I m really a blockhead. Now I understand everything that he wrote.
– user199925
Jul 25 at 13:34
add a comment |Â