If m is positive but not greater than 3 then show that the roots of the equation (m-2)x2 - (8-2m)x - (8-3m) = 0 are real . find the range of values of m for which one root is positive and the other root is negative
Dear Student,
(m-2) x2 - (8-2m)x - (8-3m) = 0
Comparing it with ax2 +bx +c = 0
a = (m-2) , b = -(8-2m) , c = -(8-3m)
D = b2 - 4ac
For roots to be real D must be greater than equal to 0.
Therefore,
D = (8-2m)2 - 4(m-2) (-(8-3m))
= 64 - 32m + 4m2 + 4 (8m - 3m2 - 16 + 6m2 )
= 4 (16 - 8m + m2 + 8m + 3m2 - 16)
= 4 (4m2 )
= 16 m2
Hence, D is grater than 0 and the roots are real
Now, one root is positive and other negative
Hence, product of roots is less than 0
Product of roots = < 0
Regards
(m-2) x2 - (8-2m)x - (8-3m) = 0
Comparing it with ax2 +bx +c = 0
a = (m-2) , b = -(8-2m) , c = -(8-3m)
D = b2 - 4ac
For roots to be real D must be greater than equal to 0.
Therefore,
D = (8-2m)2 - 4(m-2) (-(8-3m))
= 64 - 32m + 4m2 + 4 (8m - 3m2 - 16 + 6m2 )
= 4 (16 - 8m + m2 + 8m + 3m2 - 16)
= 4 (4m2 )
= 16 m2
Hence, D is grater than 0 and the roots are real
Now, one root is positive and other negative
Hence, product of roots is less than 0
Product of roots = < 0
Regards