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If lim(xrarr0)(1+px+qx^(2))^("cosec "x)=...

If `lim_(xrarr0)(1+px+qx^(2))^("cosec "x)=2048`, then the value of `(p)/(11)` is equal to (take `ln2=0.69`)

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To solve the limit problem given in the question, we will follow these steps: ### Step 1: Rewrite the Limit We start with the limit: \[ \lim_{x \to 0} (1 + px + qx^2)^{\csc x} \] We know that \(\csc x = \frac{1}{\sin x}\), so we can rewrite the limit as: \[ \lim_{x \to 0} (1 + px + qx^2)^{\frac{1}{\sin x}} \] ### Step 2: Analyze the Form of the Limit As \(x\) approaches 0, \(1 + px + qx^2\) approaches 1. Therefore, we have the form \(1^{\infty}\), which is indeterminate. We can use the property: \[ \lim_{x \to a} (1 + f(x))^{g(x)} = e^{\lim_{x \to a} f(x)g(x)} \] if \(f(x) \to 0\) and \(g(x) \to \infty\). ### Step 3: Identify \(f(x)\) and \(g(x)\) Let: \[ f(x) = px + qx^2 \] and \[ g(x) = \csc x = \frac{1}{\sin x} \] As \(x \to 0\), \(f(x) \to 0\) and \(g(x) \to \infty\). ### Step 4: Calculate the Limit of \(f(x)g(x)\) We need to find: \[ \lim_{x \to 0} (px + qx^2) \cdot \frac{1}{\sin x} \] Using L'Hospital's Rule for the limit of the form \(0 \cdot \infty\), we rewrite it as: \[ \lim_{x \to 0} \frac{px + qx^2}{\sin x} \] This is a \(0/0\) form, so we apply L'Hospital's Rule: \[ \text{Differentiate the numerator: } p + 2qx \] \[ \text{Differentiate the denominator: } \cos x \] Thus, we have: \[ \lim_{x \to 0} \frac{p + 2qx}{\cos x} \] As \(x \to 0\), \(\cos x \to 1\), so: \[ \lim_{x \to 0} \frac{p + 2qx}{\cos x} = p \] ### Step 5: Substitute Back into the Limit Now we substitute back: \[ \lim_{x \to 0} (1 + px + qx^2)^{\csc x} = e^{p} \] We know this limit equals 2048, so: \[ e^{p} = 2048 \] ### Step 6: Express 2048 in Terms of \(e\) We can express 2048 as a power of 2: \[ 2048 = 2^{11} \] Taking the natural logarithm on both sides: \[ p = \ln(2048) = \ln(2^{11}) = 11 \ln(2) \] ### Step 7: Find \(\frac{p}{11}\) Now we need to find: \[ \frac{p}{11} = \frac{11 \ln(2)}{11} = \ln(2) \] Given that \(\ln(2) \approx 0.69\), we conclude: \[ \frac{p}{11} = 0.69 \] ### Final Answer Therefore, the value of \(\frac{p}{11}\) is: \[ \boxed{0.69} \]
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