Question 13

MATRIX MATCHHARD

Match each entry in List-I to the correct entry in List-II and choose the correct option.

List - I

P

If α\alpha and β\beta are the distinct roots of the equation x2+x+1=0x^2 + x + 1 = 0, then the quadratic equation with roots 1(α+1)2026\frac{1}{(\alpha+1)^{2026}} and 1(β+1)2026\frac{1}{(\beta+1)^{2026}} is

Q

If α\alpha and β\beta are the distinct roots of the equation x2+x+1=0x^2 + x + 1 = 0, then the quadratic equation with roots 1(α+1)2027\frac{1}{(\alpha+1)^{2027}} and 1(β+1)2027\frac{1}{(\beta+1)^{2027}} is

R

If γ\gamma and δ\delta are the distinct roots of the equation x2−x+1=0x^2 - x + 1 = 0, then the value of 1(γ−1)2026+1(δ−1)2026\frac{1}{(\gamma-1)^{2026}} + \frac{1}{(\delta-1)^{2026}} is

S

If pp and rr are the distinct roots of the equation x2+x−1=0x^2 + x - 1 = 0, then the value of 1(p+1)3+1(r+1)3\frac{1}{(p+1)^3} + \frac{1}{(r+1)^3} is

List-II

1

x2+x+1=0x^2 + x + 1 = 0

2

x2−x+1=0x^2 - x + 1 = 0

3

x2+x−1=0x^2 + x - 1 = 0

4

−1-1

5

−4-4

(A)

(P) → (1), (Q) → (2), (R) → (5), (S) → (4)

(B)

(P) → (3), (Q) → (1), (R) → (4), (S) → (5)

(C)

(P) → (1), (Q) → (2), (R) → (4), (S) → (5)

(D)

(P) → (2), (Q) → (3), (R) → (5), (S) → (4)

Detailed Solution

For (P) and (Q), roots of x2+x+1=0x^2 + x + 1 = 0 are ω\omega and ω2\omega^2.

Since α+1=−α2\alpha + 1 = -\alpha^2 and α3=1\alpha^3 = 1:

(P) New roots are 1(−α2)2026=1α4052\frac{1}{(-\alpha^2)^{2026}} = \frac{1}{\alpha^{4052}}.

Since 4052≡2(mod3)4052 \equiv 2 \pmod 3, roots are 1α2=α\frac{1}{\alpha^2} = \alpha and 1β2=β\frac{1}{\beta^2} = \beta.

The equation remains x2+x+1=0x^2 + x + 1 = 0. Thus (P) → (1).

(Q) New roots are 1(−α2)2027=−1α4054=−1α=−α2\frac{1}{(-\alpha^2)^{2027}} = \frac{-1}{\alpha^{4054}} = \frac{-1}{\alpha} = -\alpha^2. The roots are −ω2-\omega^2 and −ω-\omega. Sum =1= 1, Product =1= 1.

Equation is x2−x+1=0x^2 - x + 1 = 0. Thus (Q) → (2).

(R) Roots of x2−x+1=0x^2 - x + 1 = 0 are −ω,−ω2-\omega, -\omega^2. Let γ=−ω\gamma = -\omega. Then γ−1=−ω−1=ω2\gamma - 1 = -\omega - 1 = \omega^2.

Value =1(ω2)2026+1(ω)2026=1ω2+1ω=ω+ω2=−1= \frac{1}{(\omega^2)^{2026}} + \frac{1}{(\omega)^{2026}} = \frac{1}{\omega^2} + \frac{1}{\omega} = \omega + \omega^2 = -1. Thus (R) → (4).

(S) Roots of x2+x−1=0x^2 + x - 1 = 0 satisfy p+1=1pp+1 = \frac{1}{p}.

Value =p3+r3=(p+r)3−3pr(p+r)=(−1)3−3(−1)(−1)=−1−3=−4= p^3 + r^3 = (p+r)^3 - 3pr(p+r) = (-1)^3 - 3(-1)(-1) = -1 - 3 = -4. Thus (S) → (5).

Matching sequence: (P) → (1), (Q) → (2), (R) → (4), (S) → (5).

Correct Option: C

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