Question

1的2次方-2的2次方+3的2次方-4的2次方+5的2次方-的2次方·····+99的2次方-100的2次方

Answer 1

n^2-(n+1)^2=n^2-(n^2+2n+1)=-(2n+1) 所以原式=-(3+7+11+..+199) =-(3+199)/2*50=-5050