JEE MATHEMATICS MCQ: FUNCTIONS

1 Easy

1 of 1

Application +4 | -1

Let

f

be a function satisfying

f(x y)=\frac{f(x)}{y}

for all positive real number

x

and

y

. If

f(30)=20

then the value

f(40)

View answer and explanation

Correct option: A

Option A (15) is correct because using the given functional equation

f(xy) = \frac{{f(x)}}{{y}}

and the value

f(30) = 20

, we can find

f(40)

More Questions from FUNCTIONS

Practice All Chapter MCQs →

f:(-\infty, 2] \longrightarrow(-\infty, 4]

f(x)=x(4-x)

f^{-1}(x)

g(f(x))=|\sin x|

f(g(x))=(\sin \sqrt{x})^2

f:\left( {2,\;3} \right) \to \left( {0,\;1} \right)

f\left( x \right) = x - \left[ x \right]

{f^{ - 1}}\left( x \right)

f: R \rightarrow R

f(x)=x^4

f(x)=(x+1)^2-1(x \geq-1)

S=\left\{x: f(x)=f^{-1}(x)\right\}