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The number of real roots of the equation...

The number of real roots of the equation
`1+a_(1)x+a_(2)x^(2)+………..a_(n)x^(n)=0`, where `|x| lt (1)/(3)` and `|a_(n)| lt 2`, is

A

n if n is even

B

1 if n is odd

C

0 for any ` n in N`

D

None of these

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The correct Answer is:
To solve the equation \[ 1 + a_1 x + a_2 x^2 + \ldots + a_n x^n = 0 \] given the conditions \( |x| < \frac{1}{3} \) and \( |a_n| < 2 \), we will analyze the polynomial and its roots step by step. ### Step 1: Understanding the Polynomial We start with the polynomial: \[ P(x) = 1 + a_1 x + a_2 x^2 + \ldots + a_n x^n \] We need to find the number of real roots of this polynomial under the given constraints. ### Step 2: Analyzing the Constraints We know that: 1. \( |x| < \frac{1}{3} \) implies that \( x \) is restricted to the interval \( (-\frac{1}{3}, \frac{1}{3}) \). 2. \( |a_n| < 2 \) indicates that the leading coefficient \( a_n \) is bounded. ### Step 3: Evaluating the Polynomial at the Boundaries Let’s evaluate the polynomial at the boundaries of the interval \( x = -\frac{1}{3} \) and \( x = \frac{1}{3} \): 1. **At \( x = -\frac{1}{3} \)**: \[ P\left(-\frac{1}{3}\right) = 1 + a_1\left(-\frac{1}{3}\right) + a_2\left(-\frac{1}{3}\right)^2 + \ldots + a_n\left(-\frac{1}{3}\right)^n \] This value will depend on the coefficients \( a_1, a_2, \ldots, a_n \). 2. **At \( x = \frac{1}{3} \)**: \[ P\left(\frac{1}{3}\right) = 1 + a_1\left(\frac{1}{3}\right) + a_2\left(\frac{1}{3}\right)^2 + \ldots + a_n\left(\frac{1}{3}\right)^n \] Similarly, this value will also depend on the coefficients. ### Step 4: Finding the Values of the Polynomial Since \( |a_n| < 2 \), we can say that the polynomial will not reach zero within the interval \( (-\frac{1}{3}, \frac{1}{3}) \) because: - The polynomial \( P(x) \) is continuous. - The values at the boundaries will not allow the polynomial to cross the x-axis. ### Step 5: Conclusion Since the polynomial does not change sign in the interval \( (-\frac{1}{3}, \frac{1}{3}) \) and does not equal zero at the boundaries, we conclude that there are no real roots within the specified range. Thus, the number of real roots of the equation is: \[ \text{Number of real roots} = 0 \] ### Final Answer The number of real roots of the equation is **0**. ---
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OBJECTIVE RD SHARMA ENGLISH-MISCELLANEOUS EQUATIONS AND INEQUATIONS -Chapter Test
  1. The number of roots of the equation [sin^(-1)x]=x-[x], is

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  2. The number of values of a for which the system of equations 2^(|x|)+|x...

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  3. The number of real solutions (x, y, z, t) of simultaneous equations 2y...

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  4. If the sum of the greatest integer less than or equal to x and the lea...

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  5. If x,y and z are real such that x+y+z=4, x^(2)+y^(2)+z^(2)=6, x belong...

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  6. Consider the equation : x^(2)+198x+30=2sqrt(x^(2)+18x+45)

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  7. x^(8)-x^(5)-(1)/(x)+(1)/(x^(4)) gt 0, is satisfied for

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  8. The number of solutions of the equation ((1+e^(x^(2)))sqrt(1+x^(2)))...

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  9. The number of real roots of the equation 1+a(1)x+a(2)x^(2)+………..a(n)...

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  10. Let a,b be integers and f(x) be a polynomial with integer coefficients...

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  11. Let Pn(ix) =1+2x+3x^2+............+(n+1)x^n be a polynomial such that...

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  12. Let Pn(x) =1+2x+3x^2+............+(n+1)x^n be a polynomial such that ...

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  13. Let Pn(ix) =1+2x+3x^2+............+(n+1)x^n be a polynomial such that...

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  14. The number of negative real of x^(4)-4x-1=0, is

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  15. Find the number of positive real roots of x^4-4x-1=0

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  16. The number of negative real of x^(4)-4x-1=0, is

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  17. Let f(x) be defined by f(x) = x- [x], 0!=x in R, where [x] is the grea...

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  18. The complete set of values of x satisfying the equation x^(2)*2^(x+1)+...

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  19. The numebr of solution (s) of the inequation sqrt(3x^(2)+6x+7)+sqrt(...

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  20. The number of real solutions of 1+|e^x-1|=e^x(e^x-2)

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