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If the function f(x)={(x+a^(2)sqrt(2)...

If the function
`f(x)={(x+a^(2)sqrt(2)sinx",", 0 le x lt (pi)/(4)),(x cot x+b",",(pi)/(4) le x lt (pi)/(2)),(b sin 2x-a cos 2x",", (pi)/(2) le x le pi):}`
is continuous in the interval `[0,pi]` then the values of (a, b) are

A

`(0,0)`

B

`(0,(1)/(2))`

C

`(0,1)`

D

`(-1,1)`

Text Solution

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The correct Answer is:
To determine the values of \( a \) and \( b \) such that the function \[ f(x) = \begin{cases} x + a^2 \sqrt{2} \sin x & \text{for } 0 \leq x < \frac{\pi}{4} \\ x \cot x + b & \text{for } \frac{\pi}{4} \leq x < \frac{\pi}{2} \\ b \sin 2x - a \cos 2x & \text{for } \frac{\pi}{2} \leq x \leq \pi \end{cases} \] is continuous on the interval \([0, \pi]\), we need to ensure continuity at the points \( x = \frac{\pi}{4} \) and \( x = \frac{\pi}{2} \). ### Step 1: Continuity at \( x = \frac{\pi}{4} \) For continuity at \( x = \frac{\pi}{4} \), we need: \[ \lim_{x \to \frac{\pi}{4}^-} f(x) = \lim_{x \to \frac{\pi}{4}^+} f(x) \] Calculating the left-hand limit: \[ \lim_{x \to \frac{\pi}{4}^-} f(x) = \frac{\pi}{4} + a^2 \sqrt{2} \sin\left(\frac{\pi}{4}\right) = \frac{\pi}{4} + a^2 \sqrt{2} \cdot \frac{1}{\sqrt{2}} = \frac{\pi}{4} + a^2 \] Calculating the right-hand limit: \[ \lim_{x \to \frac{\pi}{4}^+} f(x) = \frac{\pi}{4} \cot\left(\frac{\pi}{4}\right) + b = \frac{\pi}{4} \cdot 1 + b = \frac{\pi}{4} + b \] Setting the two limits equal gives: \[ \frac{\pi}{4} + a^2 = \frac{\pi}{4} + b \] Thus, we have: \[ a^2 = b \quad \text{(1)} \] ### Step 2: Continuity at \( x = \frac{\pi}{2} \) For continuity at \( x = \frac{\pi}{2} \), we need: \[ \lim_{x \to \frac{\pi}{2}^-} f(x) = \lim_{x \to \frac{\pi}{2}^+} f(x) \] Calculating the left-hand limit: \[ \lim_{x \to \frac{\pi}{2}^-} f(x) = \frac{\pi}{2} \cot\left(\frac{\pi}{2}\right) + b = \frac{\pi}{2} \cdot 0 + b = b \] Calculating the right-hand limit: \[ \lim_{x \to \frac{\pi}{2}^+} f(x) = b \sin(2 \cdot \frac{\pi}{2}) - a \cos(2 \cdot \frac{\pi}{2}) = b \cdot 0 - a \cdot (-1) = a \] Setting the two limits equal gives: \[ b = a \quad \text{(2)} \] ### Step 3: Solving the equations From equation (1) \( a^2 = b \) and equation (2) \( b = a \), we can substitute \( b \) from equation (2) into equation (1): \[ a^2 = a \] Rearranging gives: \[ a^2 - a = 0 \] Factoring out \( a \): \[ a(a - 1) = 0 \] Thus, \( a = 0 \) or \( a = 1 \). ### Step 4: Finding corresponding \( b \) 1. If \( a = 0 \): \[ b = 0 \] So one solution is \( (a, b) = (0, 0) \). 2. If \( a = 1 \): \[ b = 1 \] So another solution is \( (a, b) = (1, 1) \). ### Final Answer The values of \( (a, b) \) are \( (0, 0) \) and \( (1, 1) \). ---

To determine the values of \( a \) and \( b \) such that the function \[ f(x) = \begin{cases} x + a^2 \sqrt{2} \sin x & \text{for } 0 \leq x < \frac{\pi}{4} \\ x \cot x + b & \text{for } \frac{\pi}{4} \leq x < \frac{\pi}{2} \\ b \sin 2x - a \cos 2x & \text{for } \frac{\pi}{2} \leq x \leq \pi ...
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Knowledge Check

  • If the function f(x) = {{:(x+a root(2)(2)sinx, 0 lt= xlt(pi)/(4)), (x cotx +b, (pi)/(4) lt= x lt (pi)/(2)), (b sin 2x -a cos 2x , (pi)/(2) lt= x lt= pi):} is continuous in the interval [0, pi ], then the values of a and b are respectively

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    B
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    C
    (0,1)
    D
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  • If f(x)={(x+a sqrt(2) sinx"," ,0 lt x lt (pi)/(4)),(2x cotx+b",",(pi)/(4) le x le (pi)/(2)),(a cos 2x-b sinx",", (pi)/(2) lt x le pi):} is continuous at x=(pi)/(4) , then a - b is equal to

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  • The function f(x) = {{:(x + asqrt(2) sin x, 0 le x lt pi//4),(2x cotx +6, pi//4 le x le pi//2),(a cos 2x-b sin x, pi//2 lt x le pi):} is continuous for 0 le x le pi then a, b are

    A
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    B
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    C
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    D
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