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Let f(x)=x^(3)-x^(2)-3x-1, g(x)=(x+1)a a...

Let `f(x)=x^(3)-x^(2)-3x-1, g(x)=(x+1)a and h(x)=(f(x))/(g(x))` where h is a rational function such that
(i) It is continuous everywhere except when `x=-1`,
(ii) `lim_(xrarr -1)h(x)=(1)/(2)`.
The value of h(1) is

A

`1//2`

B

`1//4`

C

`-1//2`

D

1

Text Solution

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The correct Answer is:
To solve the problem step by step, we will analyze the functions given and find the value of \( h(1) \). ### Step 1: Define the functions We have: - \( f(x) = x^3 - x^2 - 3x - 1 \) - \( g(x) = (x + 1)a \) - \( h(x) = \frac{f(x)}{g(x)} \) ### Step 2: Factor \( f(x) \) To find the value of \( h(x) \), we first need to factor \( f(x) \). We can check if \( x + 1 \) is a factor by substituting \( x = -1 \): \[ f(-1) = (-1)^3 - (-1)^2 - 3(-1) - 1 = -1 - 1 + 3 - 1 = 0 \] Since \( f(-1) = 0 \), \( x + 1 \) is indeed a factor of \( f(x) \). ### Step 3: Perform polynomial long division We divide \( f(x) \) by \( x + 1 \): 1. Divide \( x^3 \) by \( x \) to get \( x^2 \). 2. Multiply \( x^2 \) by \( x + 1 \) to get \( x^3 + x^2 \). 3. Subtract: \( f(x) - (x^3 + x^2) = -2x^2 - 3x - 1 \). 4. Divide \( -2x^2 \) by \( x \) to get \( -2x \). 5. Multiply \( -2x \) by \( x + 1 \) to get \( -2x^2 - 2x \). 6. Subtract: \( -2x^2 - 3x - 1 - (-2x^2 - 2x) = -x - 1 \). 7. Divide \( -x \) by \( x \) to get \( -1 \). 8. Multiply \( -1 \) by \( x + 1 \) to get \( -x - 1 \). 9. Subtract: \( -x - 1 - (-x - 1) = 0 \). Thus, we have: \[ f(x) = (x + 1)(x^2 - 2x - 1) \] ### Step 4: Rewrite \( h(x) \) Now, substituting \( f(x) \) into \( h(x) \): \[ h(x) = \frac{(x + 1)(x^2 - 2x - 1)}{(x + 1)a} \] For \( x \neq -1 \), we can simplify: \[ h(x) = \frac{x^2 - 2x - 1}{a} \] ### Step 5: Find the limit as \( x \to -1 \) We are given that: \[ \lim_{x \to -1} h(x) = \frac{1}{2} \] Calculating the limit: \[ \lim_{x \to -1} h(x) = \frac{(-1)^2 - 2(-1) - 1}{a} = \frac{1 + 2 - 1}{a} = \frac{2}{a} \] Setting this equal to \(\frac{1}{2}\): \[ \frac{2}{a} = \frac{1}{2} \] Cross-multiplying gives: \[ 4 = a \] ### Step 6: Calculate \( h(1) \) Now that we have \( a = 4 \), we can find \( h(1) \): \[ h(1) = \frac{1^2 - 2(1) - 1}{4} = \frac{1 - 2 - 1}{4} = \frac{-2}{4} = -\frac{1}{2} \] ### Final Answer The value of \( h(1) \) is: \[ \boxed{-\frac{1}{2}} \]

To solve the problem step by step, we will analyze the functions given and find the value of \( h(1) \). ### Step 1: Define the functions We have: - \( f(x) = x^3 - x^2 - 3x - 1 \) - \( g(x) = (x + 1)a \) - \( h(x) = \frac{f(x)}{g(x)} \) ...
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