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Home  >>  CBSE XII  >>  Math  >>  Relations and Functions

Let $ f:N\rightarrow R$ be the function defined by $f(x)=\frac{2x-1}{2}\;and\;g:\;Q \rightarrow R $ be another function defined by g(x)=x+2. Then $(g\;o\;f)\frac{3}{2}$ is

$\begin{array}{1 1}(A)\;1 & (B)\;1\\(C)\;\large\frac{7}{2} & (D)\;none\;of\;these.\end{array}$

1 Answer

Toolbox:
  • $(gof)(x)=g(f(x))$
$f:N \to R$
 
$f(x)=\frac{2x-1}{2}$
 
$g(x)=g: Q \to R$ be
 
$g(x)=x+2$
 
$(gof)(x)=(gof)^{3/2}$
 
$=g(f(3/2))$
 
But f is defined form $N \to R$
 
f is not defined for 3/2 hence
 
'D' option is correct

 

 

answered Mar 5, 2013 by meena.p
 
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