Exams › JEE Advanced › Maths
The system of equations: x + (sin a)*y + (sin² a)*z = 0 x + (cos a)*y + (cos² a)*z = 0 x + (sin 2a)*y + (sin² 2a)*z = 0 has non-trivial solutions. How many distinct values of a exist in [0, pi]?
- 1
- 2
- 3
- 4
Correct answer: 3
Solution
The determinant of the matrix with rows (1, p, p²), (1, q, q²), (1, r, r²) equals (q-p)(r-p)(r-q), where p=sin a, q=cos a, r=sin 2a. The determinant is zero when any two are equal. Solving sin a = cos a, sin a = sin 2a, and cos a = sin 2a on [0, pi] gives 3 distinct values.
Related JEE Advanced Maths questions
- What is the nature of the solution for the equations x + y + z = 3, 2x + y + 2z = 5, and x − y + 3z = 3?
- What is the nature of the solutions for the equations x + y + z = 3, 2x + 2y + 2z = 7, and x − y + 3z = 3?
- Consider the matrix M = [0 1 a; 1 2 3; 3 b 1] and its adjugate adj M = [-1 1 -1; 8 -6 2; -5 3 -1], where a and b are real numbers. Which of the following statements is/are true?
- Given that the 3x3 determinant |x, 2, x; x², x, 6; x, 1, x| equals Ax⁴ + Bx³ + Cx² + Dx + E, find the sum of the digits of the square of (5A + 4B + 3C + 2D + E).
- The determinant with rows (x², (y+z)², yz), (y², (x+z)², zx), (z², (x+y)², xy) is divisible by which of the following?
- Consider the determinant equation: det([[a1 + b1*x, a1*x + b1, c1], [a2 + b2*x, a2*x + b2, c2], [a3 + b3*x, a3*x + b3, c3]]) = 0. Which of the following are possible conditions that guarantee this holds for all choices of ai, bi, ci?
⚔️ Practice JEE Advanced Maths free + battle 1v1 →