solve this one.

JEE Main 2015 Coaching › Algebra questions › solve this one.

If â€˜headâ€™ means one and â€˜tailâ€™ means two , then coefficient of quadratic equation
ax2 + bx + c = 0 are chosen by tossing three fair coins. Then find the probability that roots of the equations are imaginary.

jaldi post karna poora solution ke saath

#Mathematics #Algebra

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3 Answers

106

Asish Mahapatra ·2009-03-31 07:29:59

head - 1
tails - 2

CASES..
HHH or 111 here D<0 so imaginary roots
HHT or 112 here D<0
HTH or 121 here D=0
HTT or 122 here D<0
THH or 211 here D<0
THT or 212 here D<0
TTH or 221 here D<0
TTT or 222 here D<0

Now probability of HTH = 1/8..

So probablity of imaginary roots = 1-1/8 = 7/8?

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1

voldy ·2009-03-31 23:19:13

you've taken H-2 and T-1 ???

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106

Asish Mahapatra ·2009-03-31 23:34:16

edited that : but still same answer ?

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Your Answer

Basic Integral Calculus Operators Symbols Matrix Cases

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° ∂ ∞ α β γ δ θ λ μ ν ξ π ρ σ φ ω ε ƒ κ τ υ Γ Δ Λ Σ Π Ω