If alpha = 1 + sum_r=1^6 (-3)^r-1 ^12 C_2r-1, then the distance of the point (12, sqrt3) from the line alpha x - sqrt3 y + 1 = 0 is

Numerical Answer Type:
Enter a numerical value Answer: 5 to 5 +4 marks

Solution & Explanation

### Related Formula Perpendicular distance from a point (x_1, y_1) to a line Ax + By + C = 0: d = frac|Ax_1 + By_1 + C|sqrtA^2 + B^2 ### Core Logic Rewrite the summation for alpha by embedding complex roots to isolate alternating terms: alpha = 1 + frac1sqrt3i left[ frac(1 + sqrt3i)^12 - (1 - sqrt3i)^122 right] Using complex cube roots of unity conversions (1 + sqrt3i = -2omega^2), this simplifies directly to alpha = 1. ### Step 1: Calculating Perpendicular Distance Substitute alpha = 1 into the line equation, yielding x - sqrt3y + 1 = 0. Evaluating the distance from point (12, sqrt3): d = frac|12 - sqrt3(sqrt3) + 1|sqrt1^2 + (-sqrt3)^2 = frac|12 - 3 + 1|2 = frac102 = 5 ### Pattern Recognition Binomial series containing terms like sqrt3^2r-1 collapse neatly into simple geometric forms using standard complex rotations (e^ipi/3). ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Binomial Theorem Class 11 Maths: Straight Lines

Reference Study Guides

More Straight Lines Previous-Year Questions — Page 5

Q2 jee_main_2024_31_jan_evening Centroid and Orthocentre
Let A (a, b), B(3, 4) and (-6, -8) respectively denote the centroid, circumcentre and orthocentre of a triangle. Then, the distance of the point P(2a + 3, 7b + 5) from the line 2x + 3y - 4 = 0 measured parallel to the line x - 2y - 1 = 0 is
  • A. frac15 sqrt57
  • B. frac17sqrt56
  • C. frac17 sqrt57
  • D. fracsqrt517

Solution

### Related Formula textCentroid divides the line joining Orthocentre and Circumcentre in 2:1 Distance in parametric form: x = x_1 + rcostheta, y = y_1 + rsintheta ### Core Logic
Centroid and Orthocentre diagram for Q2 - JEE Main 2024 Evening
Centroid and Orthocentre diagram for Q2 - JEE Main 2024 Evening
Let Orthocentre C(-6, -8) and Circumcentre B(3, 4). Centroid A(a, b) divides CB in 2:1. a = frac2(3) + 1(-6)2+1 = 0 b = frac2(4) + 1(-8)2+1 = 0 So, P(2a+3, 7b+5) = (3, 5). The line along which distance is measured is parallel to x - 2y - 1 = 0, giving slope m = tantheta = frac12. Using parametric coordinates from P(3,5): x = 3 + rcostheta, quad y = 5 + rsintheta Substitute into the target line 2x + 3y - 4 = 0: 2(3 + rcostheta) + 3(5 + rsintheta) - 4 = 0 r(2costheta + 3sintheta) = -17 From tantheta = 1/2, we get sintheta = frac1sqrt5 and costheta = frac2sqrt5. rleft(2left(frac2sqrt5right) + 3left(frac1sqrt5right)right) = -17 rleft(frac7sqrt5right) = -17 implies |r| = frac17sqrt57 ### Pattern Recognition Standard Euler line property: O, G, C are collinear and G divides OC in 2:1. Use parametric equation to find intersection distance directly without finding the intersection point. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Straight Lines
Q23 jee_main_2024_31_jan_evening Parallelogram Properties
Let A(-2, -1), B(1, 0), C(alpha, beta) and D(gamma, delta) be the vertices of a parallelogram ABCD. If the point C lies on 2x - y = 5 and the point D lies on 3x - 2y = 6, then the value of |alpha + beta + gamma + delta| is equal to
Numerical Answer. Answer: 32 to 32

Solution

### Related Formula textIn a parallelogram, midpoints of diagonals coincide: left(fracx_A+x_C2, fracy_A+y_C2right) = left(fracx_B+x_D2, fracy_B+y_D2right) ### Core Logic
Parallelogram Properties diagram for Q23 - JEE Main 2024 Evening
Parallelogram Properties diagram for Q23 - JEE Main 2024 Evening
Given diagonals AC and BD bisect each other: alpha - 2 = gamma + 1 implies alpha - gamma = 3 quad dots (1) beta - 1 = delta + 0 implies beta - delta = 1 quad dots (2) Point C(alpha, beta) lies on 2x - y = 5 implies 2alpha - beta = 5 quad dots (3) Point D(gamma, delta) lies on 3x - 2y = 6 implies 3gamma - 2delta = 6 quad dots (4) From (1) and (2), substitute gamma = alpha - 3 and delta = beta - 1 into (4): 3(alpha - 3) - 2(beta - 1) = 6 3alpha - 9 - 2beta + 2 = 6 implies 3alpha - 2beta = 13 quad dots (5) Solve (3) and (5): From (3), beta = 2alpha - 5. Substitute in (5): 3alpha - 2(2alpha - 5) = 13 -alpha + 10 = 13 implies alpha = -3 So, beta = 2(-3) - 5 = -11. From earlier substitutions: gamma = -3 - 3 = -6 delta = -11 - 1 = -12 Sum of variables: |alpha + beta + gamma + delta| = |-3 - 11 - 6 - 12| = |-32| = 32 ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Straight Lines
Q10 jee_main_2024_31_jan_morning Properties of Parallelogram
Let alpha, beta, gamma, delta in Z and let A (alpha, beta), B (1, 0), C (gamma, delta) and D (1, 2) be the vertices of a parallelogram ABCD. If AB = sqrt10 and the points A and C lie on the line 3y = 2x + 1, then 2(alpha + beta + gamma + delta) is equal to
  • A. 10
  • B. 5
  • C. 12
  • D. 8

Solution

### Core Logic Let E be the midpoint of the diagonals AC and BD. Since ABCD is a parallelogram, the diagonals bisect each other.
Properties of Parallelogram diagram for Q10 - JEE Main 2024 Morning
Properties of Parallelogram diagram for Q10 - JEE Main 2024 Morning
Midpoint E from BD: left( frac1+12, frac0+22 right) = (1, 1). ### Step 1: Apply Midpoint on AC Midpoint E from AC: left( fracalpha+gamma2, fracbeta+delta2 right). Equating both: fracalpha+gamma2 = 1 implies alpha + gamma = 2 fracbeta+delta2 = 1 implies beta + delta = 2 ### Step 2: Final Value The expression requires 2(alpha + beta + gamma + delta). 2(2 + 2) = 2(4) = 8 *(Note: Additional conditions like AB = sqrt10 and the line equation are extraneous data not needed to find the sum).* ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Straight Lines

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