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lim(xto0)(ae^(2x)-bcosx+c)/(xsinx)=1 the...

`lim_(xto0)(ae^(2x)-bcosx+c)/(xsinx)=1` then `a+b+c` is equal to .__________

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To solve the limit problem given by \[ \lim_{x \to 0} \frac{ae^{2x} - b\cos x + c}{x \sin x} = 1, \] we will follow these steps: ### Step 1: Evaluate the limit at \( x = 0 \) First, we substitute \( x = 0 \) into the expression: - \( e^{2x} \) approaches \( e^0 = 1 \) - \( \cos x \) approaches \( \cos(0) = 1 \) - \( \sin x \) approaches \( \sin(0) = 0 \) Thus, the expression becomes: \[ \frac{a(1) - b(1) + c}{0} = \frac{a - b + c}{0}. \] This indicates that the limit is in the form \( \frac{0}{0} \), which is indeterminate. ### Step 2: Apply L'Hôpital's Rule Since we have a \( \frac{0}{0} \) form, we can apply L'Hôpital's Rule. We differentiate the numerator and the denominator separately. **Numerator:** - The derivative of \( ae^{2x} \) is \( 2ae^{2x} \). - The derivative of \( -b\cos x \) is \( b\sin x \). - The derivative of \( c \) is \( 0 \). Thus, the derivative of the numerator is: \[ 2ae^{2x} + b\sin x. \] **Denominator:** - The derivative of \( x \sin x \) is \( \sin x + x\cos x \). ### Step 3: Rewrite the limit using derivatives Now we rewrite the limit: \[ \lim_{x \to 0} \frac{2ae^{2x} + b\sin x}{\sin x + x\cos x}. \] ### Step 4: Substitute \( x = 0 \) again Substituting \( x = 0 \) again: - The numerator becomes \( 2a(1) + b(0) = 2a \). - The denominator becomes \( 0 + 0(1) = 0 \). This again gives us a \( \frac{0}{0} \) form, so we apply L'Hôpital's Rule again. ### Step 5: Differentiate again **Numerator:** - The derivative of \( 2ae^{2x} \) is \( 4ae^{2x} \). - The derivative of \( b\sin x \) is \( b\cos x \). Thus, the new numerator is: \[ 4ae^{2x} + b\cos x. \] **Denominator:** - The derivative of \( \sin x + x\cos x \) is \( \cos x + (\cos x - x\sin x) = 2\cos x - x\sin x \). ### Step 6: Rewrite the limit again Now we have: \[ \lim_{x \to 0} \frac{4ae^{2x} + b\cos x}{2\cos x - x\sin x}. \] ### Step 7: Substitute \( x = 0 \) once more Substituting \( x = 0 \): - The numerator becomes \( 4a(1) + b(1) = 4a + b \). - The denominator becomes \( 2(1) - 0 = 2 \). Thus, we have: \[ \frac{4a + b}{2} = 1. \] ### Step 8: Solve for \( a \) and \( b \) Multiplying both sides by 2 gives: \[ 4a + b = 2. \] ### Step 9: Use the original limit condition From the first limit condition, we also have: \[ a - b + c = 0. \] ### Step 10: Solve the system of equations Now we have two equations: 1. \( 4a + b = 2 \) 2. \( a - b + c = 0 \) From equation 1, we can express \( b \) in terms of \( a \): \[ b = 2 - 4a. \] Substituting this into equation 2: \[ a - (2 - 4a) + c = 0 \implies a - 2 + 4a + c = 0 \implies 5a + c = 2. \] ### Step 11: Solve for \( c \) Now we can express \( c \): \[ c = 2 - 5a. \] ### Step 12: Find \( a + b + c \) Now we can find \( a + b + c \): \[ a + b + c = a + (2 - 4a) + (2 - 5a) = a + 2 - 4a + 2 - 5a = -8a + 4. \] ### Step 13: Find \( a \) To find \( a \), we can set \( a = 0 \) (from previous deductions). Substituting \( a = 0 \): \[ b = 2 - 4(0) = 2, \] \[ c = 2 - 5(0) = 2. \] ### Final Calculation Thus, we have: \[ a + b + c = 0 + 2 + 2 = 4. \] ### Conclusion The value of \( a + b + c \) is \[ \boxed{4}. \]

To solve the limit problem given by \[ \lim_{x \to 0} \frac{ae^{2x} - b\cos x + c}{x \sin x} = 1, \] we will follow these steps: ...
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