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Alog(x+x2+a)

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Question

`log (x + sqrt(x^2 + "a"))`

Sum
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Solution

Let y = `log (x + sqrt(x^2 + "a"))`

Differentiating both sides w.r.t. x

`"dy"/"dx" = "d"/"dx" log (x + sqrt(x^2 + "a"))`

= `1/(x + sqrt(x^2 + "a")) * "d"/"dx" (x + sqrt(x^2 + "a"))`

=  `1/(x + sqrt(x^2 + "a")) * [1 + 1/(2sqrt(x^2 + "a")) xx "d"/"dx" (x^2 + "a")]`

= `1/(x + sqrt(x^2 + "a")) * [1 + 1/(2sqrt(x^2 + "a")) * 2x]`

= `1/(x + sqrt(x^2 + "a")) * [1 + x/(sqrt(x^2 + "a"))]`

= `1/(x + sqrt(x^2 + "a")) * ((sqrt(x^2 + "a") + x)/(sqrt(x^2 + "a")))`

= `1/(sqrt(x^2 + "a")`

Hence. `"dy"/"dx" = 1/sqrt(x^2 + "a")`

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Chapter 5: Continuity And Differentiability - Exercise [Page 109]

APPEARS IN

NCERT Exemplar Mathematics Exemplar [English] Class 12
Chapter 5 Continuity And Differentiability
Exercise | Q 27 | Page 109

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