The problem has two parts. Part 1: Given a quadratic equation $7x^2 - 2x + 1 = 0$ with roots $a$ and $b$, we need to form a quadratic equation with integral coefficients whose roots are $\frac{1}{a}$ and $\frac{1}{b}$. Part 2: Given three consecutive numbers $p-4$, $p+2$, and $3p+1$ in a geometric progression (G.P.), we need to find the two possible values of the common ratio of the G.P.

AlgebraQuadratic EquationsRoots of EquationsGeometric ProgressionSequences and Series
2025/6/30

1. Problem Description

The problem has two parts.
Part 1: Given a quadratic equation 7x22x+1=07x^2 - 2x + 1 = 0 with roots aa and bb, we need to form a quadratic equation with integral coefficients whose roots are 1a\frac{1}{a} and 1b\frac{1}{b}.
Part 2: Given three consecutive numbers p4p-4, p+2p+2, and 3p+13p+1 in a geometric progression (G.P.), we need to find the two possible values of the common ratio of the G.P.

2. Solution Steps

Part 1:
For the quadratic equation 7x22x+1=07x^2 - 2x + 1 = 0, the sum of the roots is a+b=27=27a+b = -\frac{-2}{7} = \frac{2}{7} and the product of the roots is ab=17ab = \frac{1}{7}.
We need to find a quadratic equation whose roots are 1a\frac{1}{a} and 1b\frac{1}{b}.
The sum of the new roots is 1a+1b=a+bab=2717=2\frac{1}{a} + \frac{1}{b} = \frac{a+b}{ab} = \frac{\frac{2}{7}}{\frac{1}{7}} = 2.
The product of the new roots is 1a1b=1ab=117=7\frac{1}{a} \cdot \frac{1}{b} = \frac{1}{ab} = \frac{1}{\frac{1}{7}} = 7.
A quadratic equation with roots 1a\frac{1}{a} and 1b\frac{1}{b} can be written as
x2(sum of roots)x+(product of roots)=0x^2 - (\text{sum of roots})x + (\text{product of roots}) = 0
x22x+7=0x^2 - 2x + 7 = 0
Part 2:
Since p4,p+2,3p+1p-4, p+2, 3p+1 are in geometric progression, the ratio between consecutive terms is constant. Therefore,
p+2p4=3p+1p+2\frac{p+2}{p-4} = \frac{3p+1}{p+2}
(p+2)2=(p4)(3p+1)(p+2)^2 = (p-4)(3p+1)
p2+4p+4=3p2+p12p4p^2 + 4p + 4 = 3p^2 + p - 12p - 4
p2+4p+4=3p211p4p^2 + 4p + 4 = 3p^2 - 11p - 4
0=2p215p80 = 2p^2 - 15p - 8
2p216p+p8=02p^2 - 16p + p - 8 = 0
2p(p8)+1(p8)=02p(p-8) + 1(p-8) = 0
(2p+1)(p8)=0(2p+1)(p-8) = 0
Thus, p=8p = 8 or p=12p = -\frac{1}{2}.
Case 1: p=8p=8
The numbers are 84=48-4=4, 8+2=108+2=10, 3(8)+1=253(8)+1=25.
The common ratio is 104=52\frac{10}{4} = \frac{5}{2} and 2510=52\frac{25}{10} = \frac{5}{2}.
So, the common ratio is 52\frac{5}{2}.
Case 2: p=12p=-\frac{1}{2}
The numbers are 124=92-\frac{1}{2} - 4 = -\frac{9}{2}, 12+2=32-\frac{1}{2} + 2 = \frac{3}{2}, 3(12)+1=32+1=123(-\frac{1}{2}) + 1 = -\frac{3}{2} + 1 = -\frac{1}{2}.
The common ratio is 3292=39=13\frac{\frac{3}{2}}{-\frac{9}{2}} = \frac{3}{-9} = -\frac{1}{3} and 1232=13=13\frac{-\frac{1}{2}}{\frac{3}{2}} = \frac{-1}{3} = -\frac{1}{3}.
So, the common ratio is 13-\frac{1}{3}.

3. Final Answer

Part 1: The required quadratic equation is x22x+7=0x^2 - 2x + 7 = 0.
Part 2: The two possible values of the common ratio are 52\frac{5}{2} and 13-\frac{1}{3}.

Related problems in "Algebra"

We are given the function $y = a \sin \theta + b \cos \theta$ where $0 \le \theta < 2\pi$. The funct...

TrigonometryMaximum and Minimum ValuesTrigonometric FunctionsAmplitude and Phase Shift
2025/6/30

The problem asks to simplify the expression $\sqrt{48} - \sqrt{75} + \sqrt{12}$ and find the correct...

SimplificationRadicalsSquare Roots
2025/6/30

The problem asks to find the analytical expression of the function $f(x)$ whose graph is shown. The ...

Piecewise FunctionsParabolaLinear EquationsHyperbolaFunction Analysis
2025/6/29

The graph of a function $f(x)$ is given. The function consists of a parabolic arc with vertex $V$, a...

Piecewise FunctionsQuadratic FunctionsLinear FunctionsRational FunctionsFunction Analysis
2025/6/29

The problem is to determine the equation of the function represented by the graph. The graph appears...

FunctionsPiecewise FunctionsQuadratic FunctionsLinear FunctionsHyperbolasGraphing
2025/6/28

The image shows a piecewise function. We need to define the function $f(x)$ based on the graph. The ...

Piecewise FunctionsParabolaLinear FunctionsHyperbolaFunction DefinitionGraph Analysis
2025/6/28

The problem asks to find the general term for the sequence 1, 5, 14, 30, 55, ...

SequencesSeriesPolynomialsSummation
2025/6/27

The problem asks us to find the axis of symmetry and the vertex of the graph of the given quadratic ...

Quadratic FunctionsVertex FormAxis of SymmetryParabola
2025/6/27

The problem asks us to sketch the graphs of the following two quadratic functions: (1) $y = x^2 + 1$...

Quadratic FunctionsParabolasGraphingVertex FormTransformations of Graphs
2025/6/27

Given two complex numbers $Z_a = 1 + \sqrt{3}i$ and $Z_b = 2 - 2i$, we are asked to: I. Convert $Z_a...

Complex NumbersPolar FormDe Moivre's TheoremComplex Number MultiplicationComplex Number DivisionRoots of Complex Numbers
2025/6/27