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Find the values of a and b such that the function defined by f(x) = {5, if ЁЭСе тЙд 2, ЁЭСОтБвЁЭСе + ЁЭСП, if 2 < ЁЭСе < 10, 21, if ЁЭСе тЙе 10 is a continuous function. - Mathematics

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Find the values of a and b such that the function defined by f(x) = `{(5", if"  x <= 2),(ax +b", if"  2 < x < 10),(21", if"  x >= 10):}` is a continuous function.

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f(x) = `{(5", if"  x <= 2),(ax +b", if"  2 < x < 10),(21", if"  x >= 10):}`

Since f(x) = 5, f(x) = ax + b, f(x) is a continuous function at 21 times, f(x) is already a continuous function at x < 2, 2 < x < 10, x > 10.

If f(x) is continuous at x = 2, this implies:

f(2) = `lim_(x -> 2^+)` f(x) = `lim_(x -> 2^-)` f(x)

⇒ 5 = a(2) + b 

⇒ 2a + b = 5   ...(1)

If f(x) is continuous at x = 10, this implies:

f(10) = `lim_(x -> 10^+)` f(x) = `lim_(x -> 10^-)` f(x)

⇒ 21 = a(10) + b

⇒ 10a + b  = 21   ...(2)

Subtracting equation (2) from (1),

⇒ 8a = 16

⇒ a = `16/8`

⇒ a = 2

Put a = 2 in equation (1)

⇒ 2(2) + b  = 5

⇒ 4 + b = 5

⇒ b = 5 − 4

⇒ b = 1

That is, the function f(x) is continuous for the quantities a = 2, b = 1.

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рдкрд╛рда 5: Continuity and Differentiability - Exercise 5.1 [рдкреГрд╖реНрда резремрез]

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рдПрдирд╕реАрдИрдЖрд░рдЯреА Mathematics Part 1 and 2 [English] Class 12
рдкрд╛рда 5 Continuity and Differentiability
Exercise 5.1 | Q 30 | рдкреГрд╖реНрда резремрез

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