If alpha and beta are the roots of the equation 2z^2 - 3z - 2i = 0 , where i = sqrt-1 , then 16 cdot mathrmReleft(fracalpha^19 + beta^19 + alpha^11 + beta^11alpha^15 + beta^15right) cdot operatornameImleft(fracalpha^19 + beta^19 + alpha^11 + beta^11alpha^15 + beta^15right) is equal to :

Solution & Explanation

### Related Formula Since alpha and beta are roots of 2z^2 - 3z - 2i = 0, they satisfy the quadratic equation directly, meaning: 2alpha^2 - 3alpha - 2i = 0 implies 2left(alpha - fracialpharight) = 3 implies alpha - fracialpha = frac32 Similarly for beta: beta - fracibeta = frac32 ### Core Logic Square the baseline relation to transition to higher exponential powers: left(alpha - fracialpharight)^2 = left(frac32right)^2 implies alpha^2 - frac1alpha^2 - 2i = frac94 alpha^2 - frac1alpha^2 = frac94 + 2i Squaring once more to isolate the fourth powers: left(alpha^2 - frac1alpha^2right)^2 = left(frac94 + 2iright)^2 alpha^4 + frac1alpha^4 - 2 = frac8116 - 4 + 9i alpha^4 + frac1alpha^4 = frac4916 + 9i ### Step 1: Simplify the Target Expression Fraction Rearrange the given complex algebraic fraction by factoring out powers: fracalpha^19 + alpha^11 + beta^19 + beta^11alpha^15 + beta^15 = fracalpha^15left(alpha^4 + frac1alpha^4right) + beta^15left(beta^4 + frac1beta^4right)alpha^15 + beta^15 Since both alpha and beta satisfy the exact same symmetric relational identity: alpha^4 + frac1alpha^4 = beta^4 + frac1beta^4 = frac4916 + 9i Substitute this uniform value back into the algebraic expression: = frac(alpha^15 + beta^15)left(frac4916 + 9iright)alpha^15 + beta^15 = frac4916 + 9i ### Step 2: Extract Real and Imaginary Components From our simplified expression: mathrmRe = frac4916 operatornameIm = 9 Now, substitute these into the evaluation formula: textResult = 16 cdot left(frac4916right) cdot 9 = 49 cdot 9 = 441 ### Pattern Recognition Symmetric rational polynomials in roots alpha, beta that can be split into identical numeric multipliers for alpha^n and beta^n allow direct cancellation of the polynomial bases without evaluating the individual roots explicitly. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Mathematics: Complex Numbers

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Q26 jee_main_2024_31_jan_morning Properties of Modulus and Argument
If alpha denotes the number of solutions of |1 - i|^x = 2^x and beta = left(frac|z|arg(z)right), where z = fracpi4 (1 + i)^4 left(frac1 - sqrtpi isqrtpi + i + fracsqrtpi - i1 + sqrtpi iright), i = sqrt-1, then the distance of the point (alpha, beta) from the line 4x - 3y = 7 is
Numerical Answer. Answer: 3 to 3

Solution

### Core Logic |1 - i|^x = 2^x implies (sqrt2)^x = 2^x implies 2^x/2 = 2^x This implies fracx2 = x implies x = 0. There is exactly 1 solution, so alpha = 1. ### Step 1: Simplify complex number z (1+i)^4 = ((1+i)^2)^2 = (1 + i^2 + 2i)^2 = (2i)^2 = -4 Thus, z = -pi left( frac(1-sqrtpii)(sqrtpi-i)pi + 1 + frac(sqrtpi-i)(1-sqrtpii)1 + pi right) ### Step 2: Simplify Bracket Let's expand the terms directly: z = fracpi4(-4) left[ fracsqrtpi - pi i - i - sqrtpipi + 1 + fracsqrtpi - i - pi i - sqrtpi1 + pi right] = -pi left[ frac-i(pi+1)pi+1 + frac-i(pi+1)pi+1 right] = -pi [ -i - i ] = 2pi i ### Step 3: Find beta For z = 2pi i: |z| = 2pi and arg(z) = fracpi2. beta = frac|z|arg(z) = frac2pipi/2 = 4 ### Step 4: Distance from Line Distance of point (alpha, beta) = (1, 4) from the line 4x - 3y - 7 = 0: D = frac|4(1) - 3(4) - 7|sqrt4^2 + (-3)^2 = frac|4 - 12 - 7|5 = frac|-15|5 = 3 ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Complex Numbers and Quadratic Equations Class 11 Maths: Straight Lines

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