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Let f(x) = log(e) x and g(x) =(x^(4) -2...

Let `f(x) = log_(e) x and g(x) =(x^(4) -2x^(3) + 3x^(2) - 2x+2)/(2x^(2) - 2x + 1)`
Then , the domain of fog (x) is

A

`R`

B

`[0, oo)`

C

`(0, oo)`

D

`[1, oo)`

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The correct Answer is:
To find the domain of the composite function \( f(g(x)) \), where \( f(x) = \log_e x \) and \( g(x) = \frac{x^4 - 2x^3 + 3x^2 - 2x + 2}{2x^2 - 2x + 1} \), we need to ensure that \( g(x) > 0 \) since the logarithm function is only defined for positive values. ### Step 1: Analyze the denominator of \( g(x) \) The denominator of \( g(x) \) is \( 2x^2 - 2x + 1 \). We need to check if this expression is always positive. 1. Calculate the discriminant \( D \) of the quadratic: \[ D = b^2 - 4ac = (-2)^2 - 4 \cdot 2 \cdot 1 = 4 - 8 = -4 \] Since the discriminant is negative, the quadratic does not have real roots and is always positive (as the coefficient of \( x^2 \) is positive). ### Step 2: Analyze the numerator of \( g(x) \) Next, we need to analyze the numerator \( x^4 - 2x^3 + 3x^2 - 2x + 2 \) to determine when it is greater than zero. 1. We can factor or analyze the numerator. We can check for roots using the Rational Root Theorem or synthetic division, but a more straightforward approach is to evaluate the expression at various points. 2. Evaluate \( g(x) \) at specific points: - At \( x = 0 \): \[ g(0) = \frac{0^4 - 2 \cdot 0^3 + 3 \cdot 0^2 - 2 \cdot 0 + 2}{2 \cdot 0^2 - 2 \cdot 0 + 1} = \frac{2}{1} = 2 > 0 \] - At \( x = 1 \): \[ g(1) = \frac{1^4 - 2 \cdot 1^3 + 3 \cdot 1^2 - 2 \cdot 1 + 2}{2 \cdot 1^2 - 2 \cdot 1 + 1} = \frac{1 - 2 + 3 - 2 + 2}{2 - 2 + 1} = \frac{2}{1} = 2 > 0 \] - At \( x = 2 \): \[ g(2) = \frac{2^4 - 2 \cdot 2^3 + 3 \cdot 2^2 - 2 \cdot 2 + 2}{2 \cdot 2^2 - 2 \cdot 2 + 1} = \frac{16 - 16 + 12 - 4 + 2}{8 - 4 + 1} = \frac{10}{5} = 2 > 0 \] 3. Since \( g(x) \) is a polynomial of degree 4, and we have evaluated it at several points and found it to be positive, we can conclude that \( g(x) > 0 \) for all \( x \). ### Conclusion Since \( g(x) > 0 \) for all \( x \), the domain of \( f(g(x)) \) is all real numbers. Thus, the domain of \( f(g(x)) \) is: \[ \text{Domain of } f(g(x)) = (-\infty, \infty) \]

To find the domain of the composite function \( f(g(x)) \), where \( f(x) = \log_e x \) and \( g(x) = \frac{x^4 - 2x^3 + 3x^2 - 2x + 2}{2x^2 - 2x + 1} \), we need to ensure that \( g(x) > 0 \) since the logarithm function is only defined for positive values. ### Step 1: Analyze the denominator of \( g(x) \) The denominator of \( g(x) \) is \( 2x^2 - 2x + 1 \). We need to check if this expression is always positive. 1. Calculate the discriminant \( D \) of the quadratic: \[ ...
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OBJECTIVE RD SHARMA ENGLISH-REAL FUNCTIONS -Section I - Solved Mcqs
  1. If f(x) =1- x, x in [-3,3], then the domain of fof (x) is

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  2. If f(x) = sqrt(2-x) and g(x) = sqrt(1-2x), then the domain of fog (x)...

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  3. Let f(x) = log(e) x and g(x) =(x^(4) -2x^(3) + 3x^(2) - 2x+2)/(2x^(2)...

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  4. Let f(x) be a function whose domain is [-5,7]. Let g(x)=|2x+5|, then d...

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  5. The domain of f(x) = (log(2) (x+3))/(x^(2) + 3x +2), is

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  6. The domain of definition of f (x) = sin ^(-1) {log(2)(x^(2) + 3x + 4)}...

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  7. The domain of definition of f(x)=sin^(- 1)[2-4x^2] is ([.] denotes the...

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  8. The domain of the function f(x)=sqrt(x^2-[x]^2) , where [x] is the gre...

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  9. The domain of definition of f(x)=cos^(- 1)(x+[x]) is

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  10. The domain of definition of the functions f(x) = log(e)(x-[x]), is

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  11. If f(x) = [x] and g(x) = {x}= fraction part of x, then for any two ...

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  12. The domain of definition of f(x) = log(2) (log(3) (log(4) x)), is

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  13. The domain of the function f(x)=log2[log3(log4(x^2-3x+6)}]i s .

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  14. The domain of definition of the function f(x)=sqrt(log(10) ((2-x)/(x)...

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  15. The domain of definition of the function f(x) = sqrt(log(x^(2)-1)) x i...

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  16. Find the domain f(x)=sqrt(log(10){(log(10)x)/(2(3-log(10)x))})

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  17. The domain of definition of the function f(x) = log(3) {-log(1//2)(1+(...

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  18. If [x] denote the greater integer less than or equal to x, then the...

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  19. If e ^(x)+e^(f(x))=e, then for f (x) domain is:

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  20. The domain of f(x)i s(0,1)dot Then the domain of (f(e^x)+f(1n|x|) is (...

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