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Evaluate the following limits: limx→3x2-81x-3

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प्रश्न

Evaluate the following limits:

`lim_(sqrt(x) -> 3) (x^2 - 81)/(sqrt(x) - 3)`

योग
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उत्तर

`lim_(sqrt(x) -> 3) (x^2 - 81)/(sqrt(x) - 3)`

Put `sqrt(x) - y`,

When `sqrt(x) -> 3`,

We have y → 3

`lim_(sqrt(x) -> 3) (x^2 - 81)/(sqrt(x) - 3) = lim_(sqrt(x) -> 3) (((sqrt(x)^2))^2 - 3^4)/(sqrt(x) - 3)`

= `lim_(sqrt(x) -> 3) ((sqrt(x))^4 - 3^4)/(sqrt(x) - 3)`

= `lim_(y -> 3) (y^4 - 3^4)/(y - 3)`

`lim_(x -> "a") (x^"n" - "a"^"n")/(x - "a") = "na"^("n" - 1)`

= `4(3)^(4 -1)`

= 4 × 33

`lim_(sqrt(x) -> 3) (x^2 - 81)/(sqrt(x) - 3)` = 4 × 27

= 108

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 9: Differential Calculus - Limits and Continuity - Exercise 9.2 [पृष्ठ १०२]

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सामाचीर कलवी Mathematics - Volume 1 and 2 [English] Class 11 TN Board
अध्याय 9 Differential Calculus - Limits and Continuity
Exercise 9.2 | Q 3 | पृष्ठ १०२

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