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MathsMediumMCQ2020 · 07 Jan Shift 2

Q53.Let a1, a2, a3, … , be a G. P. such that a1 < 0, a1 + a2 = 4 and a3 + a4 = 16. If ∑9i=1 ai = 4λ, then λ, is equal to. (1) −513 (2) −171 (3) 171 (4) 5113

What This Question Tests

This question involves determining a condition for a complex fraction to be real, finding the value of tan(theta), and then calculating the argument of another complex number based on this angle.

Concepts Tested

Condition for a complex number to be realArgument calculationTrigonometric identities

Formulas Used

Im(z) = 0 for z to be real

Argument of z = x + iy is tan⁻¹(y/x)

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