- #1
lingling
- 22
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1.
(a) If the roots of the equation 2(x)^2 + kx + 100 = 0 are positive,
find the possible range of k.
(b) If, in addition, one root is twice the other, find the roots and the value of k.
I have tried (a), but incorrect:
discriminate > 0
k^2 - (4)(2)(100) > 0
k^2 > 800
k > + or - 20(2)^1/2
What's wrong with my calculation?
The correct ans is:k is less than or equal to - 20 (2)^1/2
2. Find the values of t for which the quadratic equation
(x)^2 - tx + t + 3 = 0 has one positive root and one negative root.
>>> I have no idea to start doing it.
The correct answer is t < -3
Can anyone help?
Wish you all have a Merry Christmas! :rofl:
(a) If the roots of the equation 2(x)^2 + kx + 100 = 0 are positive,
find the possible range of k.
(b) If, in addition, one root is twice the other, find the roots and the value of k.
I have tried (a), but incorrect:
discriminate > 0
k^2 - (4)(2)(100) > 0
k^2 > 800
k > + or - 20(2)^1/2
What's wrong with my calculation?
The correct ans is:k is less than or equal to - 20 (2)^1/2
2. Find the values of t for which the quadratic equation
(x)^2 - tx + t + 3 = 0 has one positive root and one negative root.
>>> I have no idea to start doing it.
The correct answer is t < -3
Can anyone help?
Wish you all have a Merry Christmas! :rofl: