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JEE MainMathematicsModerateMatrix and determinants

Let λ\lambda and α\alpha be real. If denote the set
of all values of
λ\lambda for which the system of linear equations
λx+(sinλ)y+(cosα)z=0\lambda x + (sin\lambda)y + (cos\alpha)z = 0
x+(cosα)y+(sinα)z=0x + (cos\alpha)y + (sin\alpha)z = 0
−x+(sinα)y−(cosα)z=0- x + (sin\alpha)y - (cos\alpha)z = 0
has a non-trivial solution, then a+b+1 is

Show answer and solution
For non-trivial solution [IMAGE] Expanding along C1,C_{1}, we get
λ=sin2α+cos2α\lambda = sin2\alpha + cos2\alpha
∴−2≤λ≤2\therefore - \sqrt{2} \leq \lambda \leq \sqrt{2}

Source: Grass-G / M-17 Mathematics Paper 26 Nov Second.docx

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