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Find number of integral values of k for which the line `3x + 4y - k = 0` , lies between the circles `x^2 + y^2 - 2x - 2y + 1 = 0` and `x^2 + y^2 - 18 x - 12 y + 113 = 0`, without cutting a chord on either of circle.

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To find the number of integral values of \( k \) for which the line \( 3x + 4y - k = 0 \) lies between the circles defined by the equations \( x^2 + y^2 - 2x - 2y + 1 = 0 \) and \( x^2 + y^2 - 18x - 12y + 113 = 0 \) without cutting a chord on either circle, we can follow these steps: ### Step 1: Find the centers and radii of the circles 1. **Circle 1**: \( x^2 + y^2 - 2x - 2y + 1 = 0 \) - Rearranging gives: \( (x-1)^2 + (y-1)^2 = 1^2 \) - Center \( C_1 = (1, 1) \), Radius \( R_1 = 1 \) 2. **Circle 2**: \( x^2 + y^2 - 18x - 12y + 113 = 0 \) - Rearranging gives: \( (x-9)^2 + (y-6)^2 = 4^2 \) - Center \( C_2 = (9, 6) \), Radius \( R_2 = 4 \) ### Step 2: Calculate the distance between the centers of the circles The distance \( d \) between the centers \( C_1 \) and \( C_2 \) is given by: \[ d = \sqrt{(9-1)^2 + (6-1)^2} = \sqrt{8^2 + 5^2} = \sqrt{64 + 25} = \sqrt{89} \] ### Step 3: Determine the conditions for the line to lie between the circles For the line to lie between the circles without cutting a chord, the distance from the center of each circle to the line must satisfy the following inequalities: \[ d_1 > R_1 \quad \text{and} \quad d_2 < d - R_2 \] ### Step 4: Calculate the distance from the center of each circle to the line The distance \( d \) from a point \( (x_0, y_0) \) to the line \( Ax + By + C = 0 \) is given by: \[ d = \frac{|Ax_0 + By_0 + C|}{\sqrt{A^2 + B^2}} \] For our line \( 3x + 4y - k = 0 \): - \( A = 3 \), \( B = 4 \), \( C = -k \) 1. **Distance from \( C_1(1, 1) \)**: \[ d_1 = \frac{|3(1) + 4(1) - k|}{\sqrt{3^2 + 4^2}} = \frac{|7 - k|}{5} \] 2. **Distance from \( C_2(9, 6) \)**: \[ d_2 = \frac{|3(9) + 4(6) - k|}{\sqrt{3^2 + 4^2}} = \frac{|27 + 24 - k|}{5} = \frac{|51 - k|}{5} \] ### Step 5: Set up the inequalities 1. For the first circle: \[ \frac{|7 - k|}{5} > 1 \implies |7 - k| > 5 \] This gives us two cases: - \( 7 - k > 5 \implies k < 2 \) - \( 7 - k < -5 \implies k > 12 \) 2. For the second circle: \[ \frac{|51 - k|}{5} < \sqrt{89} - 4 \] Calculate \( \sqrt{89} \approx 9.43 \): \[ \sqrt{89} - 4 \approx 5.43 \implies |51 - k| < 27.15 \] This gives us: - \( 51 - k < 27.15 \implies k > 23.85 \) - \( 51 - k > -27.15 \implies k < 78.15 \) ### Step 6: Combine the inequalities From the inequalities: 1. \( k < 2 \) or \( k > 12 \) 2. \( k > 23.85 \) and \( k < 78.15 \) The valid range for \( k \) is: - \( k > 23.85 \) and \( k < 78.15 \) ### Step 7: Determine the integral values of \( k \) The integral values of \( k \) satisfying \( 24 \leq k \leq 78 \) are: \[ k = 24, 25, 26, \ldots, 78 \] ### Step 8: Count the integral values The number of integral values is: \[ 78 - 24 + 1 = 55 \] ### Final Answer The number of integral values of \( k \) is \( 55 \). ---

To find the number of integral values of \( k \) for which the line \( 3x + 4y - k = 0 \) lies between the circles defined by the equations \( x^2 + y^2 - 2x - 2y + 1 = 0 \) and \( x^2 + y^2 - 18x - 12y + 113 = 0 \) without cutting a chord on either circle, we can follow these steps: ### Step 1: Find the centers and radii of the circles 1. **Circle 1**: \( x^2 + y^2 - 2x - 2y + 1 = 0 \) - Rearranging gives: \( (x-1)^2 + (y-1)^2 = 1^2 \) - Center \( C_1 = (1, 1) \), Radius \( R_1 = 1 \) ...
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