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If x+(1)/(x)=5 , then find the value of ...

If `x+(1)/(x)=5` , then find the value of `x^(2)+(1)/(x^(2))` .

A

`26`

B

`23`

C

`30`

D

`22`

Text Solution

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The correct Answer is:
To solve the equation \( x + \frac{1}{x} = 5 \) and find the value of \( x^2 + \frac{1}{x^2} \), we can follow these steps: ### Step 1: Square both sides of the equation We start with the equation: \[ x + \frac{1}{x} = 5 \] Now, we square both sides: \[ \left(x + \frac{1}{x}\right)^2 = 5^2 \] ### Step 2: Apply the square of a binomial formula Using the identity \( (a + b)^2 = a^2 + b^2 + 2ab \), we can expand the left side: \[ x^2 + 2\left(x \cdot \frac{1}{x}\right) + \frac{1}{x^2} = 25 \] Since \( x \cdot \frac{1}{x} = 1 \), we can simplify this to: \[ x^2 + 2 + \frac{1}{x^2} = 25 \] ### Step 3: Rearrange the equation Now, we can rearrange the equation to isolate \( x^2 + \frac{1}{x^2} \): \[ x^2 + \frac{1}{x^2} + 2 = 25 \] Subtract 2 from both sides: \[ x^2 + \frac{1}{x^2} = 25 - 2 \] ### Step 4: Simplify the result Now, we can simplify the right side: \[ x^2 + \frac{1}{x^2} = 23 \] Thus, the value of \( x^2 + \frac{1}{x^2} \) is \( 23 \). ### Final Answer \[ \boxed{23} \]
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MTG IIT JEE FOUNDATION-POLYNOMIALS-EXERCISE (Multiple choice Question (Level-1))
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  2. The common quantity that must be added to each term of a^(2):b^(2) to ...

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  3. One of the dimensions of the cuboid whose volume is 16x^(2)-26x+10 is

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  4. find the value of x+y+z if x^(2)+y^(2)+z^(2)=18 and xy+yz+zx=9 .

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  5. Find the remainder when the polynomial f(x)=x^(3)-3x^(2)+4x+50 is div...

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  6. The value of a for which (x+a) is a factor of the polynomial x^(3)+ax^...

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  7. Factorisation of the polynomial sqrt(3)x^(2)+11x+6sqrt(3)

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  8. If x=-2 and x^(2)+y^(2)+2xy=0 , then find y .

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  9. If x+(1)/(x)=5 , then find the value of x^(2)+(1)/(x^(2)) .

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  10. Find the value of x^(3)-8y^(3)-36xy-216 , when x=2y+6 .

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  11. Simplify : (x^(3)-4-x+4x^(2))/(x^(2)+3x-4)

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  12. Which of the following is true if (x+1) and (x+2) are factors of p(x)=...

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  13. Factorise : 6x^(3)-5x^(2)-13x+12

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  14. If p(x)=x^(3)-3x^(2)-2x+4 , then find the value of [p(2)+p(-2)-p(0)] .

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  15. If p=2-a , then a^(3)+6ap+p^(3)-8 =

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  16. The polynomial p(x)=x^(4)-2x^(3)+3x^(2)-ax+3a when divided by (x+1) le...

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  17. The values of a and b so that the polynomial x^(3)-ax^(2)-13x+b has (x...

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  18. The product (a+b)(a-b)(a^2-a b+b^2)(a^2+a b+b^2) is equal to: a^6+b^6 ...

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  19. Posible factors of x^(4)+x^(3)-7x^(2)-x+6 are

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