Consider an A.P. such that the product of its first term and the fourt...
Given Information:
- We have an arithmetic progression (A.P.).
- The product of the first term and the fourth term is 32 less than the product of the second and third term.
- The sum of the first 4 terms of the A.P. is equal to 12.
Solution:
Let's consider the terms of the A.P. as a, a + d, a + 2d, a + 3d.
Product of First and Fourth Term:
According to the given information, the product of the first term (a) and the fourth term (a + 3d) is 32 less than the product of the second term (a + d) and the third term (a + 2d).
Therefore, we can write the equation as:
a * (a + 3d) = (a + d) * (a + 2d) - 32
Expanding and simplifying the equation:
a² + 3ad = a² + 3ad + 2d² - 32
The a² and 3ad terms cancel out, leaving us with:
0 = 2d² - 32
Simplifying further:
2d² = 32
d² = 16
d = ±4
Sum of First 4 Terms:
The sum of the first 4 terms of the A.P. is given as 12.
Therefore, we can write the equation as:
a + (a + d) + (a + 2d) + (a + 3d) = 12
Simplifying the equation:
4a + 6d = 12
Substituting the value of d from the previous step:
4a + 6(±4) = 12
4a ± 24 = 12
Simplifying further:
4a = 12 ± 24
4a = 36 or 4a = -12
Solving for a in both cases:
a = 9 or a = -3
Finding the Third Term:
Now, we can find the third term of the A.P. using the values of a and d.
For a = 9, d = 4:
Third term = a + 2d = 9 + 2(4) = 9 + 8 = 17
For a = -3, d = -4:
Third term = a + 2d = -3 + 2(-4) = -3 - 8 = -11
Sum of All Possible Third Terms:
The possible third terms of the A.P. are 17 and -11.
Therefore, the sum of all the possible third terms is:
17 + (-11) = 6
Therefore, the sum of all the possible third terms of the A.P. is 6.