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Discuss the continuity of the following function at the point indicated against them : f(x) =4x-2x+1+11-cos2x, for x≠0=(log2)22, for x=0} at x = 0. - Mathematics and Statistics

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प्रश्न

Discuss the continuity of the following function at the point indicated against them :

f(x)  `{:(=(4^x - 2^(x + 1) + 1)/(1 - cos 2x)",",  "for"  x ≠ 0),(= (log 2)^2/2",",  "for"  x = 0):}}` at x = 0.

योग
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उत्तर

f(0) = `(log 2)^2/2`    ...(Given)   ...(1)

`lim_(x -> 0) "f"(x) (4^x - 2^(x + 1) + 1)/(1 - cos 2x)`

= `lim_(x -> 0) ((2^x)^2 - 2(2^x) + 1)/(2sin^2x)`

= `lim_(x -> 0) (2^x - 1)^2/(2sin^2x)`

= `lim_(x -> 0) ([(2^x - 1)^2/x^2])/(2((sin^2x)/x^2)`  ...[∵ x → 0, x ≠ 0 ∴ x2 ≠ 0]

= `1/2 [lim_(x -> 0) (2^x - 1)/x]^2/[lim_(x -> 0) sinx/x]^2`

= `1/2 * (log 2)^2/(1)^2   ...[because  lim_(x -> 0) ("a"^x - 1)/x = log "a"]`

= `(log 2)^2/2`

From (1) and (2)

`lim_(x -> 0) "f"(x)` = f(0)

∴ f is continuous at x = 0

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 8: Continuity - EXERCISE 8.1 [पृष्ठ १७३]

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बालभारती Mathematics and Statistics 2 (Arts and Science) [English] Standard 11 Maharashtra State Board
अध्याय 8 Continuity
EXERCISE 8.1 | Q 8) (iii) | पृष्ठ १७३

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