The number of values of k for which both roots of equation X^2-6kX 9(k...
Solution:
The given equation is X^2-6kX+9(k^2-k+1)=0.
We need to find the value of k for which both roots of the equation are real, distinct and equal to almost 3.
Condition for real and distinct roots:
For real and distinct roots, the discriminant of the equation should be greater than 0. The discriminant of the given equation is:
D = b^2 - 4ac
Here, a=1, b=-6k and c=9(k^2-k+1)
D = (-6k)^2 - 4(1)(9(k^2-k+1))
D = 36k^2 - 36(k^2-k+1)
D = 72k - 36
D = 36(2k - 1)
For real and distinct roots, D > 0
36(2k - 1) > 0
2k - 1 > 0
k > 1/2
Condition for roots equal to almost 3:
We are given that both roots are equal to almost 3. Let the roots be p and q.
p + q = 6k/1 = 6k
pq = 9(k^2-k+1)/1 = 9k^2 - 9k + 9
Since both roots are almost 3, we have:
p = q = 3 + a (where a is a small quantity)
p + q = 6 + 2a
pq = (3+a)^2 = 9 + 6a + a^2
Substituting these values in the above equations, we get:
6 + 2a = 6k
9 + 6a + a^2 = 9k^2 - 9k + 9
Simplifying these equations, we get:
a = 3k - 3
a^2 - 3a + 3 = 3k^2 - 3k
Substituting the value of a, we get:
(3k-3)^2 - 3(3k-3) + 3 = 3k^2 - 3k
Simplifying this equation, we get:
9k^2 - 33k + 27 = 0
Dividing both sides by 3, we get:
3k^2 - 11k + 9 = 0
Solving this quadratic equation, we get:
k = 1 or k = 3/2
But k > 1/2 (from the condition for real and distinct roots)
Therefore, the only value of k for which both roots of the equation are real, distinct and equal to almost 3 is:
k = 3/2
Hence, the number of values of k is 1.
The number of values of k for which both roots of equation X^2-6kX 9(k...
Take D=0
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