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If Lt(x to a)(x^(9)-a^(9))/(x-a)=Lt(xto5...

If `Lt_(x to a)(x^(9)-a^(9))/(x-a)=Lt_(xto5)(x+4)` then all possible values of a are
(i) 2, 3
(ii) -2, 2
(iii) -1, 1
(iv) -3, 3

A

2,3

B

`-2,2`

C

`-1,1`

D

`-3,3`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to evaluate the limit expression given in the question. Let's break it down step by step. ### Step 1: Write the limit expression We have: \[ \lim_{x \to a} \frac{x^9 - a^9}{x - a} = \lim_{x \to 5} (x + 4) \] ### Step 2: Apply L'Hôpital's Rule Since both the numerator and denominator approach 0 as \( x \) approaches \( a \), we can apply L'Hôpital's Rule. This states that if we have a limit of the form \( \frac{0}{0} \), we can take the derivative of the numerator and the denominator. Taking the derivative: - Derivative of the numerator \( x^9 - a^9 \) with respect to \( x \) is \( 9x^8 \). - Derivative of the denominator \( x - a \) with respect to \( x \) is \( 1 \). Thus, we can rewrite the limit as: \[ \lim_{x \to a} \frac{9x^8}{1} = 9a^8 \] ### Step 3: Evaluate the right-hand side limit Now, we evaluate the right-hand side: \[ \lim_{x \to 5} (x + 4) = 5 + 4 = 9 \] ### Step 4: Set the two limits equal to each other Now we can set the two limits equal to each other: \[ 9a^8 = 9 \] ### Step 5: Simplify the equation Dividing both sides by 9 gives: \[ a^8 = 1 \] ### Step 6: Solve for \( a \) The equation \( a^8 = 1 \) implies: \[ a = 1 \quad \text{or} \quad a = -1 \] ### Conclusion Thus, the possible values of \( a \) are \( 1 \) and \( -1 \). The final answer is: \[ \text{All possible values of } a \text{ are } -1 \text{ and } 1. \] ### Answer Options The correct option is (iii) -1, 1. ---
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ICSE-LIMITS AND DERIVATIVES -Multiple Choice Questions
  1. Lt(xto0)(x)/(sin3x) is equal to (i) 3 (ii) 1/3 (iii) 0 (iv) 1

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  2. Lt(xto0)(sqrt(4+x)-2)/(sinx) is equal to (i) 4 (ii) 1 (iii) 1/4...

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  3. If Lt(x to a)(x^(9)-a^(9))/(x-a)=Lt(xto5)(x+4) then all possible value...

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  4. Let f(x)={:{(x+2",",xle-1),(cx^(2)",",xgt-1):} If Lt(xto-1) f(x) exist...

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  5. lim{x\rightarrow 0}(1-cos2x)/(sin^(2)2x) is equal to

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  6. Lt(x to0)(tan3x-2x)/(3x-sin^(2)x) is equal to

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  7. lim{x\rightarrow 0}(1-cosmx)/(1-cos nx) is equal to

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  8. lim{x\rightarrow 0}(cosx-cos3x)/(x(sin 3x-sinx)) is equal to

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  9. Lt(xto0)((1-cos2x)sin5x)/(x^(2)sin3x) is equal to (i) (6)/(5) (ii...

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  10. If Lim(x to 0) k . cosec x=Lim(x to 0)x cosec kx, then k is (i) -1,1...

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  11. Lt(x to pi)(sinx)/(x-pi) is equal to

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  12. Lt(xto1)(sinpix)/(x-1) is equal to

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  13. Lt(x to (pi)/(2))(2x-pi)/(cos x) is equal to

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  14. Lt(x to (pi)/(2))(pi/2-x)tan x is equal to (i) 1 (ii) -1 (iii) (pi)...

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  15. (lim)(x->pi/2)(tan2x)/(x-pi/2)

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  16. Lt(x to 0)(e^(x)+sinx-1)/(3x) is equal to (i) 1/3 (ii) -1/3 (iii) 2/3...

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  17. lim(x to 2)(log(x-1))/(x-2) is equal to

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  18. lim(x to 0)(3^(2x)-2^(3x))/(x) is equal to

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  19. Lt(x to 0)(|x|)/(x) is equal to (i) 1 (ii) -1 (iii) 0 (iv) does not e...

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  20. Lt(x to (3)/(2))[x] is equal to (i) 1 (ii) -1 (iii) 2 (iv) does not e...

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