If $A=R-\begin{Bmatrix}\frac{3}{2}\end{Bmatrix}$ and function $f: A→ A $ is defined by $f(x)=\frac{3x-2}{2x-3}$, then |
$f^{-1}(x)=f(x)$ $f^{-1}(x)=-f(x)$ $fof(x)=-x$ $f^{-1}(x)=\frac{3x+2}{2x+3}$ |
$f^{-1}(x)=f(x)$ |
The correct answer is Option (1) → $f^{-1}(x)=f(x)$ $f(x)=\frac{3x-2}{2x-3},A=R-\left\{\frac{3}{2}\right\}$ Injectivity (One-to-one): $⇒f(x_1)=f(x_2)$ $⇒\frac{3x_1-2}{2x_1-3}=\frac{3x_2-2}{2x_2-3}$ $⇒(3x_1-2)(3x_2-2)=(2x_1-3)(2x_2-3)$ $⇒-9x_1+4x_1=-9x_2+4x_2$ $⇒x_1=x_2$ ∴ This is one-to-one function. Surjectivity (Onto): A function is onto if for every $y∈A$, there exists $x∈A$ such that $f(x)=y$. $⇒y(2x-3)=3x-2$ $⇒x=\frac{3y-2}{2y-3}$ ∴ f(x) is surjective. and, $f(x)=f^{-1}(x)$ |