Algebra Questions

Multiple choice general knowledge science & technology
  1. pythagoras' quadratic second function

  2. pulini's hypothesis

  3. shreedharacharya's formula

  4. ramakant root formula

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The quadratic formula x = (-b ± √(b²-4ac))/2a is correctly known as Shreedharacharya's formula, named after the ancient Indian mathematician who discovered it. Pythagoras is associated with the Pythagorean theorem, not quadratic equations. The other options are fictional names.

Multiple choice general knowledge math & puzzles
  1. (20/11)^0.5

  2. (40/11)^0.5

  3. (30/11)^0.5

  4. (50/11)^0.5

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For ax²+bx+c: sum of roots = -b/a, product = c/a. Sum of reciprocals = (sum)/(product) = (-b/a)/(c/a) = -b/c = 22. For cx²+bx+a: product = a/c = 11, so a = 11c. From -b/c = 22, b = -22c. In ax²+bx+c: difference of roots = √[(sum)² - 4(product)] = √[(-b/a)² - 4(c/a)] = √[(22c/11c)² - 4(c/11c)] = √[(2)² - 4/11] = √[4 - 4/11] = √(40/11).

Multiple choice general knowledge math & puzzles
  1. -22.5

  2. -17.5

  3. -10.5

  4. none of these

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If 1.5 is a root, substitute x = 1.5 into x² + mx + 24 = 0: (1.5)² + m(1.5) + 24 = 0, giving 2.25 + 1.5m + 24 = 0, so 1.5m = -26.25, therefore m = -26.25/1.5 = -17.5. Verification: x² - 17.5x + 24 = 0 has roots 1.5 and 16 (product = 24, sum = 17.5).

Multiple choice
  1. 105

  2. 115

  3. 85

  4. 95

  5. 185

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

First equation, x2 - 4x + A = 0 Discriminant D = 16 - 4A Roots are (4 - (16 - 4A)1/2)/2 and (4 + (16 - 4A)1/2)/2, i.e. the roots are (2-(4-A)1/2)and (2+(4-A)1/2). Obviously, q = (2+(4-A)1/2) and p = (2-(4-A)1/2) because it is written that q>p. So, q-p = 2(4-A)1/2 Second equation, x2 - 12x + B =0 Discriminant D = 144 - 4B Roots are (12 - (144 - 4B)1/2)/2 and (12 + (144 - 4B)1/2)/2, i.e. the roots are (6-(36-B)1/2)and (6+(36-B)1/2). Obviously s = (6+(36-B)1/2) and r = (6-(36-B)1/2) because it is written that s>r. So, s-r = 2(36-B)1/2 Since p, q, r and s are in AP, therefore q - p = s - r (In AP, common difference is the same) 2(4-A)1/2 = 2(36-B)1/2 Solving, we get 4-A = 36-B, i.e. B-A = 32 Now, possible combinations of (B,A) are (36,4), (35,3), (34,2), (33,1) because A<=4 as per the roots of first equation {(4-A)1/2}, otherwise roots will be complex. Also, B<=36 as per the roots of the second equation. Hence, this option is correct.  

Multiple choice
  1. ω2

  2. ∞ (infinity)

  3. 3

  4. 2

  5. 0

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

x3-3x2+3x+7=0 (x-1)3+8=0 (x-1)3=-8 (x-1)3=(-2)3 {(x-1)/(-2)}3=(1) Taking the cube root, we get (x-1)/(-2)=1,ω,ω2 Solving, we get three different values of x or α, β, γ = -1, 1-2ω, 1-2ω2 Putting the values of α, β, γ in the asked equation, (1/ω)+(1/ω)+ω2=3ω2 (As 1 can be written as ω3)(Correct Answer)

Multiple choice statistics measures of central tendency geometric and harmonic mean geometric mean mean

The harmonic mean of the roots of equation $(5+\sqrt {2})x^{2}-(4+\sqrt {5})x+8+2\sqrt {5}=0$ is

  1. $2$
  2. $4$
  3. $6$
  4. $none\ of\ these$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\begin{array}{l} \left( { 5+\sqrt { 2 }  } \right) { x^{ 2 } }-\left( { 4+\sqrt { 5 }  } \right) x+8+2\sqrt { 5 } =0 \ a=5+\sqrt { 2 }  \ b=-\left( { 4+\sqrt { 5 }  } \right)  \ c=8+2\sqrt { 5 }  \ Harmonic\, \, mean\, \, of\, \, \lambda ,\beta  \ =\frac { { 2\lambda \beta  } }{ { \lambda +\beta  } }  \ \lambda \beta =\frac { c }{ a } =\frac { { 8+2\sqrt { 5 }  } }{ { 5+\sqrt { 2 }  } }  \ \lambda +\beta =\frac { { -b } }{ a } =\frac { { 4+\sqrt { 5 }  } }{ { 5+\sqrt { 2 }  } }  \ Harmonic\, \, mean=\,  \ \frac { { 2\frac { { \left( { 8+2\sqrt { 5 }  } \right)  } }{ { 5\sqrt { 2 }  } }  } }{ { \frac { { 4+\sqrt { 5 }  } }{ { 5+\sqrt { 2 }  } }  } }  \ =\frac { { 2\left( { 8+2\sqrt { 5 }  } \right)  } }{ { 4+\sqrt { 5 }  } }  \ =4\, \, \,  \end{array}$