close
Blogtrottr
Yahoo!奇摩知識+ - 分類問答 - 科學常識 - 發問中
Yahoo!奇摩知識+ - 分類問答 - 科學常識 - 發問中 
Retargeting on Facebook?

Get more sales and conversions with Facebook retargeting. Try it free for 14 days. Set up takes just minutes!
From our sponsors
數學分數根號問題誰能解?
Oct 1st 2013, 13:34

1.

x = (5√2 + 2√5) / (5√2 - 2√5),
y = (5√2 - 2√5) / (5√2 + 2√5) = 1/x

(1)

x=(5√2 + 2√5) / (5√2 - 2√5)
=(5√2 + 2√5)²/30
=(70+20√10)/30

y=(5√2 - 2√5) / (5√2 + 2√5)
=(5√2 - 2√5)²/30
=(70-20√10)/30

∴x+y=(70+20√10)/30+(70-20√10)/30
=(70+20√10+70-20√10)/30
=140/30
=14/3

(2)

x²+y²
=(x+y)²-2xy
=(14/3)²-2*x*(1/x)
=196/9-2
=178/9

2.

√49 - √0.36 + √(-5)² - √81/4 + √1+9/16

=√49 - √0.36 + √25 - √81/4 + √25/16

=7-0.6+5-9/2+5/4

=8.15

3.

1 - 2√3 + √5 / (1-√3) (√5-√3)

=1 - 2√3 + √5(1-√3) / (1²-√3²)(√5-√3)

=1 - 2√3 + √5(1-√3) / (-2)(√5-√3)

=1 - 2√3 + √5(1-√3)(√5+√3) / (-2)(√5²-√3²)

=1 - 2√3 + √5(1-√3)(√5+√3) / (-2)(2)

=1 - 2√3 + √5(-3+√5+√3-√15) / (-4)

=1 - 2√3 + (-3√5+5+√15-5√3) / (-4)

=(5-5√3-3√5+√15-4+8√3)/ (-4)

=(1+3√3-3√5+√15)/(-4)

第三題的答案很醜,不知道題目有沒有給錯,請提問者再行確認.


This entry passed through the Full-Text RSS service — if this is your content and you're reading it on someone else's site, please read the FAQ at fivefilters.org/content-only/faq.php#publishers. Five Filters recommends:

You are receiving this email because you subscribed to this feed at blogtrottr.com.

If you no longer wish to receive these emails, you can unsubscribe from this feed, or manage all your subscriptions
arrow
arrow
    全站熱搜
    創作者介紹
    創作者 koassq 的頭像
    koassq

    線上遊戲排行榜2013/2014,進擊的巨人線上看,candy crush saga外掛,正妹寫真三圍

    koassq 發表在 痞客邦 留言(0) 人氣()