मराठी

The function f is defined by f(x)={x2,0≤x≤33x,3≤x≤10 The relation g is defined by g(x)={x2,0≤x≤23x,2≤x≤10 Show that f is a function and g is not a function. - Mathematics

Advertisements
Advertisements

प्रश्न

The function f is defined by \[f\left( x \right) = \begin{cases}x^2 , & 0 \leq x \leq 3 \\ 3x, & 3 \leq x \leq 10\end{cases}\]

The relation g is defined by \[g\left( x \right) = \begin{cases}x^2 , & 0 \leq x \leq 2 \\ 3x, & 2 \leq x \leq 10\end{cases}\]

Show that f is a function and g is not a function.

बेरीज

उत्तर

The function f is defined by

\[f\left( x \right) = \begin{cases}x^2 & 0 \leqslant x \leqslant 3 \\ 3x & 3 \leqslant x \leqslant 10\end{cases}\] 

It is observed that for 0 ≤ x < 3, f (x) = x2.
3 <  x ≤ 10, f (x) = 3x
Also, at x = 3, f(x) = 32 = 9. And
f (x) = 3 × 3 = 9.
That is, at x = 3, f (x) = 9.
Therefore, for 0 ≤ x ≤ 10, the images of f (x) are unique.
Thus, the given relation is a function.
Again,
the relation g is defined as

\[g\left( x \right) = \begin{cases}x^2 , & 0 \leqslant x \leqslant 2 \\ 3x, & 2 \leqslant x \leqslant 10\end{cases}\]
It can be observed that for x = 2, g(x) = 22 = 4 and also, 
g(x) = 3 × 2 = 6.
Hence, 2 in the domain of the relation g corresponds to two different images, i.e. 4 and 6.
Hence, this relation is not a function.
shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 3: Functions - Exercise 3.1 [पृष्ठ ८]

APPEARS IN

आरडी शर्मा Mathematics [English] Class 11
पाठ 3 Functions
Exercise 3.1 | Q 16 | पृष्ठ ८

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

Let A = {9, 10, 11, 12, 13} and let f: A → N be defined by f(n) = the highest prime factor of n. Find the range of f.


Define a function as a correspondence between two sets.

 

Let A = {−2, −1, 0, 1, 2} and f : A → Z be a function defined by f(x) = x2 − 2x − 3. Find:

(b) pre-images of 6, −3 and 5.

 

A function f : R → R is defined by f(x) = x2. Determine (a) range of f, (b) {x : f(x) = 4}, (c) [yf(y) = −1].


If  \[y = f\left( x \right) = \frac{ax - b}{bx - a}\] , show that x = f(y).

 

 


Let f and g be two real functions defined by \[f\left( x \right) = \sqrt{x + 1}\] and \[g\left( x \right) = \sqrt{9 - x^2}\] . Then, describe function: 

(iii) f g


If f(x) = cos (log x), then the value of f(x2f(y2) −

\[\frac{1}{2}\left\{ f\left( \frac{x^2}{y^2} \right) + f\left( x^2 y^2 \right) \right\}\] is
 

If x ≠ 1 and \[f\left( x \right) = \frac{x + 1}{x - 1}\] is a real function, then f(f(f(2))) is

 

The domain of definition of the function \[f\left( x \right) = \sqrt{\frac{x - 2}{x + 2}} + \sqrt{\frac{1 - x}{1 + x}}\] is 

 

The domain of the function \[f\left( x \right) = \sqrt{5 \left| x \right| - x^2 - 6}\] is

 

The range of the function \[f\left( x \right) = \frac{x + 2}{\left| x + 2 \right|}\],x ≠ −2 is

 

The range of  \[f\left( x \right) = \frac{1}{1 - 2\cos x}\] is 

 


If f(m) = m2 − 3m + 1, find f(0)


Check if the following relation is a function.


Check if the relation given by the equation represents y as function of x:

x + y2 = 9


Check if the relation given by the equation represents y as function of x:

3x − 6 = 21


If f(m) = m2 − 3m + 1, find f(x + 1)


Find x, if g(x) = 0 where g(x) = `(18 -2x^2)/7`


Solve for x.

log2 x + log4 x + log16 x = `21/4`


The equation logx2 16 + log2x 64 = 3 has,


Select the correct answer from given alternatives.

Let the function f be defined by f(x) = `(2x + 1)/(1 - 3x)` then f–1 (x) is ______.


Select the correct answer from given alternative.

The domain and range of f(x) = 2 − |x − 5| is


Answer the following:

Find whether the following function is one-one

f : R → R defined by f(x) = x2 + 5


Answer the following:

Let f : R → R be given by f(x) = x3 + 1 for all x ∈ R. Draw its graph


Answer the following:

If `log (("a" + "b")/2) = 1/2(log"a" + log"b")`, then show that a = b


Answer the following:

If b2 = ac. prove that, log a + log c = 2 log b


Answer the following:

If a2 = b3 = c4 = d5, show that loga bcd = `47/30`


Answer the following:

Find the domain of the following function.

f(x) = 5–xPx–1


Given the function f: x → x2 – 5x + 6, evaluate f(x – 1)


The data in the adjacent table depicts the length of a person's forehand and their corresponding height. Based on this data, a student finds a relationship between the height (y) and the forehand length (x) as y = ax + b, where a, b are constant.

Length ‘x’ of
forehand (in cm)
Height 'y' 
(in inches)
35 56
45 65
50 69.5
55 74

Find a and b


Let A = {1, 2, 3, 4} and B = N. Let f : A → B be defined by f(x) = x3 then, find the range of f


Mapping f: R → R which is defined as f(x) = sin x, x ∈ R will be ______ 


Find the range of the following functions given by f(x) = |x − 3|


Let f(x) = `sqrt(x)` and g(x) = x be two functions defined in the domain R+ ∪ {0}. Find (f + g)(x)


Let f(x) = `sqrt(x)` and g(x) = x be two functions defined in the domain R+ ∪ {0}. Find (f – g)(x)


The domain of the function f given by f(x) = `(x^2 + 2x + 1)/(x^2 - x - 6)` is ______.


The domain and range of the function f given by f(x) = 2 – |x – 5| is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×