早教吧 育儿知识 作业答案 考试题库 百科 知识分享

化简a^2+3/a^2-1 - a+1/a-1 +1 等于?

题目详情
化简a^2+3/a^2-1 - a+1/a-1 +1 等于?
▼优质解答
答案和解析
是(a^2+3)/(a^2-1) - (a+1)/(a-1) +1
= (a^2-1+4)/(a^2-1) - (a-1+2)/(a-1) +1
= 1 + 4/(a^2-1) - 1 - 2/(a-1) +1
= 1 + 4/(a^2-1)- 2(a+1)/(a^2-1)
= 1 - (2a +2 -4)/(a^2-1)
= 1 - 2(a - 1)/(a^2-1)
= 1 - 2/(a + 1)