Find the value of "s":
s = 1^2 - 2^2 + 3^2 - 4^2 + ... - (2006)^2 + (2007)^2
Answer:
2 015 028
Help me solve it, please?
group them by twos...
s=(1^2-2^2)+ (3^2-4^2) + ...
you should recognize this as a difference oftwo squares, the value of which is the sum of the numbers or
s= -3 -7 -11 ...
This is an arithmetic sequence, the sum is easily found. Now add 2007^2.
Or you can group them differently, which can make it even easier. Experiment.