Last updated at Feb. 25, 2017 by Teachoo

Transcript

Example 18 Find the discriminant of the equation 3x2 โ 2x + 1/3 = 0 and hence find the nature of its roots. Find them, if they are real. 3x2 โ 2x + 1/3=0 (3 ร 3๐ฅ2 โ 3 ร 2๐ฅ + 1)/3=0 9x2 โ 6x +1 = 0 ร 3 9x2 โ 6x + 1 = 0 Comparing equation with ax2 + bx + c = 0 a = 9, b = โ6 , c = 1 We know that D = b2 โ 4ac D = (โ6)2 โ 4 ร 9 ร 1 D = 36 โ 36 D = 0 Since D = 0 The given equation has two equal real roots Now using quadratic formula to find roots x = (โ ๐ ยฑ โ๐ท)/2๐ Putting values x = (โ(โ 6) ยฑ โ0)/(2 ร 9) x = (6 + 0 )/18 x = (6 )/18 x = 1/3 Hence, the roots of the equation are 1/3 , 1/3 .

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He provides courses for Mathematics from Class 9 to 12. You can ask questions here.