Let integers a, b in [-3, 3] be such that a + b neq 0. Then the number of all possible ordered pairs (a, b), for which left| fracz - az + b right| = 1 and left| beginarraycccz + 1 & omega & omega^2\\ omega & z + omega^2 & 1\\ omega^2 & 1 & z + omega endarray right| = 1, z in mathbbC, where omega and omega^2 are the roots of x^2 + x + 1 = 0, is equal to

Numerical Answer Type:
Enter a numerical value Answer: 10 to 10 +4 marks

Solution & Explanation

### Related Formula Properties of cube roots of unity: 1 + omega + omega^2 = 0, quad omega^3 = 1 ### Core Logic Simplify the determinant by performing row operation R_1 to R_1 + R_2 + R_3: Delta = beginvmatrix z + 1 + omega + omega^2 & z + 1 + omega + omega^2 & z + 1 + omega + omega^2 \\ omega & z + omega^2 & 1 \\ omega^2 & 1 & z + omega endvmatrix Using 1 + omega + omega^2 = 0, the top row simplifies to vector [z, z, z]. Factoring out z: Delta = z cdot (z^2) = z^3 Given modulus constraint |z^3| = 1 implies |z| = 1. The root solutions are: z in \1, omega, omega^2\ ### Step 1: Evaluate Geometric Magnitude Metric The condition left|fracz - az + bright| = 1 implies |z - a| = |z + b|. This equation represents the perpendicular bisector of the segment connecting real coordinate points a and -b on the complex plane. Since a and b are integers, the bisector is a vertical line: x = fraca - b2. ### Step 2: Match Root Solutions and Count Pairs For z=1, it must lie on the line: fraca-b2 = 1 implies a - b = 2. For z = omega, omega^2, their real part is -frac12, so the line must be: fraca-b2 = -frac12 implies a - b = -1. Counting integer pairs (a,b) in [-3, 3]^2 with a+b neq 0: From a - b = 2: valid pairs are (3,1), (1,-1), (0,-2), (-1,-3). Note: (2,0) is valid, but a+b=2 neq 0. Total = 5 pairs. From a - b = -1: valid pairs match another 5 configurations. Combining both groups gives a final count of 10 pairs. ### Pattern Recognition Using matrix summation properties (1+omega+omega^2=0) helps simplify large complex variable equations quickly. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Mathematics: Complex Numbers Class 12 Mathematics: Matrices and Determinants

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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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