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Discuss the continuity of the function f, where f is defined by ,,,f(x)={2x,ifx<00,if0≤x≤14x,ifx>1 - Mathematics

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प्रश्न

Discuss the continuity of the function f, where f is defined by `f(x) = {(2x , ","if x < 0),(0, "," if 0 <= x <= 1),(4x, "," if x > 1):}`

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उत्तर

`"f"("x") = {(2"x""," " if", "x" < 0),(0"," " if", 0 le "x" le 1),(4"x" "," " if", "x" > 1):}`

For x < 0, f(x) = 2x;

0 < x < 1, f(x) = 0 and

for x > 1, f(x) = 4 x is a polynomial and continuous function.

So this is a function.

At x = 0,

`lim_(x -> 0^-) "f"(x) = lim_(x -> 0^-)` (2 x)

= `lim_("h" -> 0)` [2 (0 - h)]

= `lim_("h" -> 0)` (-2h)

= - 2 × 0

= 0

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

Hence, f is continuous at x = 0.

At x = 1,

`lim_(x -> 1^-) "f"(x) = lim_(x -> 1^-)` (0) = 0

`lim_(x -> 1^+) "f"(x) = lim_(x -> 1^+)` (4x)

= `lim_("h" -> 0)` [4 (1 + h)]

= `lim_("h" -> 0)` (4 + 4h)

= 4 + 4 × 0

= 4

Hence, it is not continuous at x = 1.

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अध्याय 5: Continuity and Differentiability - Exercise 5.1 [पृष्ठ १६०]

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एनसीईआरटी Mathematics [English] Class 12
अध्याय 5 Continuity and Differentiability
Exercise 5.1 | Q 15 | पृष्ठ १६०

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