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If lim(x to 1) (1 + ax + bx^(2))^((c )/(...

If `lim_(x to 1) (1 + ax + bx^(2))^((c )/(x - 1)) = e^(3)`, then the value of a + b + bc + 2009 is…….

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To solve the limit problem given, we start with the expression: \[ \lim_{x \to 1} \left(1 + ax + bx^2\right)^{\frac{c}{x - 1}} = e^3 \] ### Step 1: Rewrite the limit We can rewrite the limit in a more manageable form. We know that if \( \lim_{x \to a} f(x) = 0 \), then we can use the exponential limit property: \[ \lim_{x \to a} f(x)^{g(x)} = e^{\lim_{x \to a} f(x) g(x)} \] Here, let \( f(x) = 1 + ax + bx^2 \) and \( g(x) = \frac{c}{x - 1} \). ### Step 2: Evaluate \( f(1) \) First, we evaluate \( f(1) \): \[ f(1) = 1 + a(1) + b(1^2) = 1 + a + b \] For the limit to be valid, \( f(1) \) must equal 1, which gives us: \[ 1 + a + b = 1 \implies a + b = 0 \] ### Step 3: Substitute \( a + b = 0 \) Since \( a + b = 0 \), we can express \( b \) in terms of \( a \): \[ b = -a \] ### Step 4: Rewrite \( f(x) \) Now substitute \( b \) back into \( f(x) \): \[ f(x) = 1 + ax - a x^2 = 1 + a(x - x^2) = 1 + a x(1 - x) \] ### Step 5: Find \( \lim_{x \to 1} f(x) \) Next, we need to evaluate the limit: \[ \lim_{x \to 1} f(x) = 1 + a(1)(1 - 1) = 1 \] ### Step 6: Evaluate \( \lim_{x \to 1} g(x) \) Now we need to evaluate \( g(x) \): \[ g(x) = \frac{c}{x - 1} \] As \( x \to 1 \), \( g(x) \to \infty \). ### Step 7: Use L'Hôpital's Rule We need to evaluate: \[ \lim_{x \to 1} \frac{f(x) - 1}{x - 1} \] Using L'Hôpital's Rule since both the numerator and denominator approach 0: \[ \lim_{x \to 1} \frac{f'(x)}{1} \] ### Step 8: Differentiate \( f(x) \) Differentiate \( f(x) \): \[ f'(x) = a + 2bx = a + 2(-a)x = a(1 - 2x) \] Now evaluate at \( x = 1 \): \[ f'(1) = a(1 - 2) = -a \] ### Step 9: Calculate the limit Thus, we have: \[ \lim_{x \to 1} \frac{f(x) - 1}{x - 1} = -a \] ### Step 10: Set up the equation Now we can set up our limit equation: \[ \lim_{x \to 1} f(x) g(x) = e^3 \implies c \cdot (-a) = 3 \implies c = -\frac{3}{a} \] ### Step 11: Substitute back Now we need to find \( a + b + bc + 2009 \): Substituting \( b = -a \): \[ a + (-a) + (-a)\left(-\frac{3}{a}\right) + 2009 = 0 + 3 + 2009 = 2012 \] ### Final Answer Thus, the final answer is: \[ \boxed{2012} \]
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