The sum of the first 25 terms of the Arithmetic Progression (AP) is -925.
We are given that the nth term of the AP is defined as t = 2 - 3n. This means an = 2 - 3n. To find the sum of the first 25 terms, we can use the formula for the sum of an AP.
Here's how to determine the sum:
-
Find the first term (a1):
Substitute n = 1 into the formula for the nth term:
a1 = 2 - 3(1) = 2 - 3 = -1 -
Find the 25th term (a25):
Substitute n = 25 into the formula for the nth term:
a25 = 2 - 3(25) = 2 - 75 = -73 -
Use the formula for the sum of the first n terms of an AP:
Sn = n/2 * (a1 + an)In this case, n = 25, a1 = -1, and a25 = -73. Therefore:
S25 = 25/2 (-1 + (-73))
S25 = 25/2 (-74)
S25 = 25 * (-37)
S25 = -925
Therefore, the sum of the first 25 terms of the AP is -925, as confirmed by the reference provided: "Therefore, sum of first 25 term is −925."