The number of discontinuities in $R$ for the function $f(x)=\frac{x-1}{x^3+6 x^2+11 x+6}$ is

The number of discontinuities in $R$ for the function $f(x)=\frac{x-1}{x^3+6 x^2+11 x+6}$ is
  1. 3
  2. 2
  3. 1
  4. 0

Solution

Given, $ \begin{aligned} & f(x)=\frac{x-1}{x^3+6 x^2+11 x+6} \\ & f(x)=\frac{x-1}{(x+1)\left(x^2+5 x+6\right)} \\ & f(x)=\frac{x-1}{(x+1)(x+2)(x+3)} \end{aligned} $ For is discontinuous, hence denominator is 0 . $ \begin{array}{ll} \Rightarrow & (x+1)(x+2)(x+3)=0 \\ \Rightarrow & x=-1,-2,-3 \end{array} $ Hence, number of discontinuous in $R$ is 3

Asked in: AP EAMCET 2019 (21 Apr Shift 1)

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