Question
Evaluate $\mathop {\lim }\limits_{x \to 3} \frac{{{x^4} - 81}}{{2{x^2} - 5x - 3}}$

Answer

Here $\mathop {\lim }\limits_{x \to 3} \frac{{{x^4} - 81}}{{2{x^2} - 5x - 3}}\left[ {\frac{0}{0}{\text{from}}} \right]$
$= \mathop {\lim }\limits_{x \to 3} \frac{{({x^2} + 9)(x + 3)(x - 3)}}{{(x - 3)(2x + 1)}}$
$= \mathop {\lim }\limits_{x \to 3} \frac{{({x^2} + 9)(x + 3)}}{{(2x + 1)}} = \frac{{({3^2} + 9)(3 + 3)}}{{(2 \times 3 + 1)}} = \frac{{108}}{7}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Find the equation of hyperbola, when foci are at ($\pm$5, 0) and transverse axis is of length 8.
A straight line moves so that the sum of the reciprocals of its intercepts made on axes is constant. Show that the line passes through a fixed point.
[Hint: $\frac{\text{x}}{\text{a}}+\frac{\text{y}}{\text{b}}=1$ where $\frac{1}{\text{a}}+\frac{1}{\text{b}}=\text{constant}=\frac{1}{\text{k}}(\text{say}).$ This implies that $\frac{\text{k}}{\text{a}}+\frac{\text{k}}{\text{b}}=1$ line passes through the fixed point (k, k).]
A box contains 1 red and 3 black balls. Two balls are drawn at random in succession without replacement. Write the sample space for this experiment.
Find the conjugate of $\frac{(3-2 i)(2+3 i)}{(1+2 i)(2-i)}$
Prove that:
$\cos\Big(\frac{3\pi}{4}+\text{x}\Big)-\cos\Big(\frac{3\pi}{4}-\text{x}\Big)=-\sqrt2\sin\text{x}$
Reduce the equation $\sqrt{3}\text{x}+\text{y}+2=0$ to:
The normal form and find p and $\alpha.$
Find the equation of the line which satisfy the given conditions:
Passing through $(2,2 \sqrt{3})$ and inclined with the x-axis at an angle of 75o.
In a series of $2 n$ observations, half of them equal to $a$ and remaining half equal $-a$. If the standard deviation of the observations is 2, then find the value of $|a|.$
Express the following complex numbers in the standard form a + ib:
$\frac{1}{(2+\text{i})^2}$
 Fill in the blanks in the following table:
  P(A) P(B) $\text{P}({\text{A}}\cap{\text{B}})$ $\text{P}({\text{A}}\cup{\text{B}})$
(i) $\frac{1}{3}$ $\frac{1}{5}$ $\frac{1}{15}$ .......
(ii) 0.35 .... 0.25 0.6
(iii) 0.5 0.35 .... 0.7