Q. Find the sum of the finite series. ∑i=150(2i−1)(2i+1)______
Simplify Expression: We start by simplifying the expression (2i−1)(2i+1) using the difference of squares formula, which states that a2−b2=(a−b)(a+b). Here, a=2i and b=1, so the expression simplifies to 4i2−1.
Distribute Summation: Next, we distribute the summation from i=1 to 50 into 4i2−1. This separates the series into two parts: ∑i=1504i2 and −∑i=1501.
Evaluate First Term: We evaluate the first term ∑i=1504i2 using the summation formula for the sum of squares, which is ∑i=1ni2=6n(n+1)(2n+1). Plugging in n=50, we get:∑i=1504i2=4×(650(50+1)(2×50+1))=4×(650×51×101)=4×62550×101=4×6257550=4×42925=171700
Evaluate Second Term: We evaluate the second term ∑i=1501 which is simply the sum of 1 repeated 50 times. This is equal to 50.
Subtract and Find Answer: Finally, we subtract the result of the second term from the first term to get the final answer: 171700−50=171650.
More problems from Sum of finite series starts from 1