Question bank/JEE Main/Mathematics
JEE MainMathematicsModerateQuadratic Equations
, x^3 + ax^2 + bx + c = 0
[IMAGE] -
(1) 3 (2) 4 (3) 5 (4) 6
Show answer and solution
n, n + 1, n + 2
sum = 3(n + 1) = - a
∴ a^2 = 9(n + 1)^2
Sum of the roots taken 2 at a time = + b
∴ n(n + 1) + (n + 1)(n + 2) + (n + 2)n + 1 = b + 1
n^2 + n + n^2 + 3n + 2 + n^2 + 2n + 1 = b + 1
∴ b + 1 = 3n^2 + 6n + 3
sum = 3(n + 1) = - a
∴ a^2 = 9(n + 1)^2
Sum of the roots taken 2 at a time = + b
∴ n(n + 1) + (n + 1)(n + 2) + (n + 2)n + 1 = b + 1
n^2 + n + n^2 + 3n + 2 + n^2 + 2n + 1 = b + 1
∴ b + 1 = 3n^2 + 6n + 3
Source: Grass-G / M-03 Paper 1 Mathematics 21-8-2020_Final.docx
Need a video for this idea?
Scan any doubt from your notes and get a whiteboard explanation.