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The value of the limit lim(x to -oo) (sq...

The value of the limit `lim_(x to -oo) (sqrt(4x^(2) - x )+2x)` is

A

`-oo`

B

`-(1)/(4)`

C

0

D

`(1)/(4)`

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The correct Answer is:
To solve the limit \( \lim_{x \to -\infty} \left( \sqrt{4x^2 - x} + 2x \right) \), we will follow these steps: ### Step 1: Analyze the expression inside the limit We start with the expression: \[ \sqrt{4x^2 - x} + 2x \] As \( x \) approaches negative infinity, both \( \sqrt{4x^2 - x} \) and \( 2x \) will be influenced by the dominant term \( 4x^2 \). ### Step 2: Factor out the dominant term We can factor out \( x^2 \) from the square root: \[ \sqrt{4x^2 - x} = \sqrt{x^2(4 - \frac{1}{x})} = |x|\sqrt{4 - \frac{1}{x}} \] Since \( x \) is approaching negative infinity, \( |x| = -x \). Thus, we have: \[ \sqrt{4x^2 - x} = -x\sqrt{4 - \frac{1}{x}} \] ### Step 3: Substitute back into the limit Now substitute this back into the limit: \[ \lim_{x \to -\infty} \left(-x\sqrt{4 - \frac{1}{x}} + 2x\right) \] This simplifies to: \[ \lim_{x \to -\infty} \left(-x\sqrt{4 - \frac{1}{x}} + 2x\right) = \lim_{x \to -\infty} x \left(-\sqrt{4 - \frac{1}{x}} + 2\right) \] ### Step 4: Analyze the limit of the square root As \( x \) approaches negative infinity, \( \frac{1}{x} \) approaches 0. Therefore: \[ \sqrt{4 - \frac{1}{x}} \to \sqrt{4} = 2 \] Thus: \[ -\sqrt{4 - \frac{1}{x}} + 2 \to -2 + 2 = 0 \] ### Step 5: Evaluate the limit Now we need to evaluate: \[ \lim_{x \to -\infty} x \cdot 0 \] This limit approaches \( 0 \) since \( x \) is multiplied by a term that approaches \( 0 \). ### Final Answer Thus, the value of the limit is: \[ \boxed{0} \]

To solve the limit \( \lim_{x \to -\infty} \left( \sqrt{4x^2 - x} + 2x \right) \), we will follow these steps: ### Step 1: Analyze the expression inside the limit We start with the expression: \[ \sqrt{4x^2 - x} + 2x \] As \( x \) approaches negative infinity, both \( \sqrt{4x^2 - x} \) and \( 2x \) will be influenced by the dominant term \( 4x^2 \). ...
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KVPY PREVIOUS YEAR-KVPY-Part A - Mathematics
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