Advertisements
Advertisements
प्रश्न
If the equation x2 − ax + 1 = 0 has two distinct roots, then
पर्याय
|a| = 2
|a| < 2
|a| > 2
None of these
उत्तर
The given quadric equation is x2 − ax + 1 = 0 , and roots are distinct.
Then find the value of a.
Here, a =1,b = a and, c = 1
As we know that `D = b^2 - 4ac`
Putting the value of a =1,b = a and, c = 1
`=(a)^2 - 4 xx 1 xx 1`
` = a^2 - 4`
The given equation will have real and distinct roots, if D > 0
`a^2- 4 > 0`
`a^2 > 4`
` a > 4`
`a > sqrt4`
`> ± 2`
Therefore, the value of |a| > 2.
APPEARS IN
संबंधित प्रश्न
The sum of a number and its reciprocal is 17/4. Find the number.
The product of Ramu's age (in years) five years ago and his age (in years) nice years later is 15. Determine Ramu's present age.
Solve the following quadratic equations by factorization:
`(3x-2)/(2x-3)=(3x-8)/(x+4)`
Find the two consecutive positive even integers whose product is 288.
The sum of the squares two consecutive multiples of 7 is 1225. Find the multiples.
If 2 is a root of the quadratic equation \[3 x^2 + px - 8 = 0\] and the quadratic equation \[4 x^2 - 2px + k = 0\] has equal roots, find the value of k.
Solve the following equation: `("a+b")^2 "x"^2 - 4 "abx" - ("a - b")^2 = 0`
By increasing the speed of a car by 10 km/hr, the time of journey for a distance of 72 km. is reduced by 36 minutes. Find the original speed of the car.
The length of a rectangle exceeds its breadth by 5 m. If the breadth were doubled and the length reduced by 9 m, the area of the rectangle would have increased by 140 m². Find its dimensions.
Solve the following equation by factorisation :
2x2 + ax – a2= 0