PROBLEM
Find the sum of squares of even numbers: 22+42+62+⋯+1002. Use 12+22+⋯+n2=61n(n+1)(2n+1).
STEP 1
Assumptions1. The given formula for the sum of squares of the first n natural numbers is 1++3+⋯+n=61n(n+1)(n+1). We need to find the sum of squares of even numbers from to100.
STEP 2
We notice that the sequence 22,42,62,82,⋯,982,1002 is a sequence of squares of the first50 even numbers. We can express each term as (2k)2 where k is a natural number from1 to50.
STEP 3
We can rewrite the sequence as ×12,×22,×32,×2,⋯,×492,×502. This is equivalent to ×(12+22+32+⋯+492+502).
STEP 4
We can use the given formula for the sum of squares of the first n natural numbers to calculate the sum in the brackets.
12+22+32+⋯+502=61×50×(50+1)×(2×50+1)
STEP 5
Now, calculate the sum in the brackets.
12+22+32+⋯+502=1×50×51×101=43,883
STEP 6
Now, we can find the sum of squares of even numbers from2 to100 by multiplying the sum we found in the brackets by4.
22+42+62+82+⋯+982+1002=4×43,883
SOLUTION
Calculate the sum of squares of even numbers from2 to100.
22+42+62+2+⋯+982+1002=4×43,883=175,532The value of 22+42+62+2+⋯+982+1002 is175,532.
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