Sequences & Series
Alternating Sum of Squares
nta_pyq_2023_apr
Grade 11
Question:
If $\gcd(m,n)=1$ and $1^2-2^2+3^2-4^2+\cdots+(2023)^2=1012m^2n$, then $m^2-n^2$ is equal to
Step-by-Step Solution
Key Concept: $1^2-2^2+\cdots-(2022)^2+(2023)^2=-(3+7+\cdots+4043)+(2023)^2=-1011\cdot2023+(2023)^2=2023\cdot1012$.
$m=17,n=7$. $m^2-n^2=240$.
Correct Answer: 1