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If `theta` is the angle between the pair of tangents drawn to the ellipse `3x^(2)+2y^(2)=5` from the point (1, 2), then the value of `tan^(2)theta` is equal to

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To find the value of \( \tan^2 \theta \) where \( \theta \) is the angle between the pair of tangents drawn to the ellipse \( 3x^2 + 2y^2 = 5 \) from the point \( (1, 2) \), we can follow these steps: ### Step 1: Write the equation of the ellipse in standard form The given ellipse is: \[ 3x^2 + 2y^2 = 5 \] Dividing both sides by 5, we get: \[ \frac{x^2}{\frac{5}{3}} + \frac{y^2}{\frac{5}{2}} = 1 \] This shows that \( a^2 = \frac{5}{3} \) and \( b^2 = \frac{5}{2} \). ### Step 2: Identify the coordinates of the point The point from which the tangents are drawn is \( (x_1, y_1) = (1, 2) \). ### Step 3: Use the formula for the pair of tangents from a point to an ellipse The equation for the pair of tangents drawn from a point \( (x_1, y_1) \) to the ellipse \( \frac{x^2}{a^2} + \frac{y^2}{b^2} = 1 \) is given by: \[ \frac{xx_1}{a^2} + \frac{yy_1}{b^2} = 1 \] Substituting \( a^2 \) and \( b^2 \): \[ \frac{xx_1}{\frac{5}{3}} + \frac{yy_1}{\frac{5}{2}} = 1 \] This simplifies to: \[ \frac{3x}{5} + \frac{2y}{5} = 1 \] Multiplying through by 5 gives: \[ 3x + 2y = 5 \] ### Step 4: Find the coefficients for the angle between the tangents The general form of the equation of the pair of tangents is: \[ Ax^2 + By^2 + 2Hxy + 2Fx + 2Gy + C = 0 \] For our case, we have: - \( A = 3 \) - \( B = 2 \) - \( H = 0 \) - \( F = -5 \) - \( G = 0 \) - \( C = 0 \) ### Step 5: Calculate \( \tan^2 \theta \) Using the formula: \[ \tan^2 \theta = \frac{2\sqrt{H^2 - AB}}{A + B} \] Substituting the values: \[ \tan^2 \theta = \frac{2\sqrt{0^2 - (3)(2)}}{3 + 2} = \frac{2\sqrt{-6}}{5} \] Since \( \tan^2 \theta \) cannot be negative, we need to use the discriminant method for the quadratic formed by the tangents. ### Step 6: Find the discriminant The discriminant \( D \) of the quadratic equation formed by the tangents is given by: \[ D = (2F)^2 - 4AB \] Substituting the values: \[ D = (-10)^2 - 4(3)(2) = 100 - 24 = 76 \] Thus, the angle \( \theta \) is given by: \[ \tan^2 \theta = \frac{D}{(A + B)^2} = \frac{76}{(5)^2} = \frac{76}{25} \] ### Final Answer Thus, the value of \( \tan^2 \theta \) is: \[ \boxed{\frac{76}{25}} \]
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