为什么3/(6n-5)(6n+1)=1/2(1/6n-5-1/6n+1)
问题描述:
为什么3/(6n-5)(6n+1)=1/2(1/6n-5-1/6n+1)
答
因为 (6n+1)-(6n-5)=1+5=6
所以 3=(1/2)[(6n+1)-(6n-5)]
所以
3/(6n-5)(6n+1)
=(1/2)[(6n+1)-(6n-5)]/(6n-5)(6n+1)
=(1/2)[1/(6n-5)-1/(6n+1)]