搜搜做题作业网两道化简题.....急
来源：学生作业帮 编辑：搜搜做题作业网作业帮 分类：数学作业 时间：2024/06/13 15:22:23
两道化简题.....急
1.2-根号5/2+根号5 2.1/三倍根号2-1
1.2-根号5/2+根号5 2.1/三倍根号2-1
解1题：
原式=(2-√5)/(2+√5)
=(2-√5)²/[(2-√5)(2+√5)]
=(4-4√5+5)/(2²-√5²)
=(9-4√5)/(4-5)
=(9-4√5)/(-1)
=4√5-9
解2题：
原式=1/(3√2-1)
=(3√2+1)/[(3√2+1)(3√2-1)]
=(3√2+1)/[(3√2)²-1²]
=(3√2+1)/(18-1)
=(3√2+1)/17
原式=(2-√5)/(2+√5)
=(2-√5)²/[(2-√5)(2+√5)]
=(4-4√5+5)/(2²-√5²)
=(9-4√5)/(4-5)
=(9-4√5)/(-1)
=4√5-9
解2题：
原式=1/(3√2-1)
=(3√2+1)/[(3√2+1)(3√2-1)]
=(3√2+1)/[(3√2)²-1²]
=(3√2+1)/(18-1)
=(3√2+1)/17