Ask Questions, Get Answers
Menu
X
JEEMAIN Crash Practice
15 Test Series
NEET Crash Practice
5 Test Series
CBSE XII
Math
JEEMAIN
Math
Physics
Chemistry
Practice Test Series
CBSE XI
Math
NEET
Physics
Chemistry
Biology - XII
Biology - XI
Olympiad class V
Math - 5 Test Series
Olympiad class VI
Math - 5 Test Series
studyplans
JEEMAIN Crash Practice
15 Test Series
NEET Crash Practice
5 Test Series
CBSE XII
Math
JEEMAIN
Math
Physics
Chemistry
Practice Test Series
CBSE XI
Math
NEET
Physics
Chemistry
Biology - XII
Biology - XI
Olympiad class V
Math - 5 Test Series
Olympiad class VI
Math - 5 Test Series
mobile
exams
ask
sample papers
tutors
pricing
sign-in
Download our FREE mobile app with 1000+ tests for CBSE, JEE MAIN, NEET
X
Search
Topics
Want to ask us a question?
Click here
Browse Questions
Student Questions
Ad
Home
>>
JEEMAIN and AIPMT
>>
Mathematics
>>
Class12
>>
Relations and Functions
0
votes
If $A=\{1,2,3,4\}\:and\:B=\{3,4,7\}$ then the no. of onto functions from $A\rightarrow B$=?
(A) 9 (B) 18 (C) 36 (D) 64
jeemain
math
class12
ch1
relations-and-functions
types of functions
medium
Share
asked
May 27, 2013
by
rvidyagovindarajan_1
edited
Aug 6, 2014
by
vijayalakshmi_ramakrishnans
Please
log in
or
register
to add a comment.
Can you answer this question?
Do not ask me again to answer questions
Please
log in
or
register
to answer this question.
1 Answer
0
votes
Toolbox:
If $n(A)=m\:and\:n(B)=n$ then, no. of onto functions from $A\rightarrow B$ is given by the formula : $\begin {align} \sum \limits _{r=1} ^ {n}\end {align} $ $ (-1)^{n-r}$ $ ^ n C_r$ $ r^m$
By taking m=4 and n= 3 we get in the above formula
$(-1)^2$ $ ^3C_1$ $1^4$ $+(-1)^1$ $ ^3C_2$ $ 2^4$ $ +(-1)^0$ $ ^3C_3$ $ 3^4$
$3-48+81=36$
answered
May 27, 2013
by
rvidyagovindarajan_1
Please
log in
or
register
to add a comment.
Related questions
0
votes
1
answer
If $f:A\rightarrow B$ is defined as $f(x)=\sqrt 3 sinx+cosx+4$ and $f$ is invertible then find A.
asked
May 28, 2013
by
rvidyagovindarajan_1
jeemain
math
class12
ch1
relations-and-functions
types of functions
medium
0
votes
1
answer
Find the linear functions that maps $[-1,1]$ onto $[0,2]$.
asked
May 28, 2013
by
rvidyagovindarajan_1
jeemain
math
class12
ch1
relations-and-functions
types of functions
difficult
0
votes
1
answer
If $f:R\rightarrow R$ is defined as $f(x)=[x]^2+[x+1]-3$ where $[x]$ is greatest integer of $x$, then what type of function is $f$?
asked
May 28, 2013
by
rvidyagovindarajan_1
jeemain
math
class12
ch1
relations-and-functions
types of functions
difficult
0
votes
1
answer
If $A=\{1,2,3,4\}$ and $B=\{1,2\}$, then the number of onto functions from $A$ to $B$ is
asked
Apr 28, 2013
by
rvidyagovindarajan_1
jeemain
math
class12
ch1
relations-and-functions
functions
medium
0
votes
1
answer
The value of $a\:\:and\:\:b$ for which $f:R\rightarrow R$ is defined as $f(x)=ax+b$ where $a,b\in R $ is bijection with $fof$ as its identity is ?
asked
May 28, 2013
by
rvidyagovindarajan_1
jeemain
math
class12
ch1
relations-and-functions
types of relations
difficult
0
votes
1
answer
Range of $f(x)=\large\frac{x-[x]}{1+x-[x]}$ where $[x]$ is greatest integer function.
asked
May 21, 2013
by
rvidyagovindarajan_1
jeemain
math
class12
ch1
relations-and-functions
types of functions
medium
0
votes
1
answer
If $f:R\rightarrow S$ defined by $\:f(x)=\sin x-\sqrt3\; \cos x+1\;$ is onto function then $S$ = ?
asked
May 4, 2013
by
rvidyagovindarajan_1
jeemain
math
class12
ch1
relations-and-functions
types
of
functions
difficult
Ask Question
Tag:
Math
Phy
Chem
Bio
Other
SUBMIT QUESTION
►
Please Wait
Take Test
JEEMAIN Crash Practice
15 Test Series
NEET Crash Practice
5 Test Series
JEEMAIN
350+ TESTS
NEET
320+ TESTS
CBSE XI MATH
50+ TESTS
CBSE XII MATH
80+ TESTS
x
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App
...