1/15/2015 vui:Anhchngchyxe(pn)|Math2IT

http://math2it.blogspot.fr/2014/10/ovuianhchangchayxe.html 1/7

Math2IT

Dinh Anh Thi | 9.10.14 | Hiu ton hc | vui | 13Like

vui: Anh chng chy xe (p n)

Mt chng trai bt u chy xe trn ng, sau khi chy lin tc 60 pht, anh pht hin mnh chy c 20 Km. C hay khng mt on no y di 10Km trong 20Km kia m anh y chylin tc trong vng 30 pht?

p n s c cng b sau khi bn c cu tr li cho ring mnh :)

Gi : p n l c v cc bn cn dng cng c ton hc gii bi ton ny. C th hn l bnhy dng nh l gi tr trung gian (hay cn gi l nh l Bolzano).

Li giiGi qung ng i c sau khong thi gian l , theo bi ta bit rng hm lin tctheo thi gian . Khi y xt hm s lin tc (y l qung ng ic t thi im ti thi im ).

Ta thy

(v theo gi thit t lc bt u, tc ti sau 60 pht, tc th ngi i c 20 Kmnn ).

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TRANG CH LATEX TON LINUX OS X CNTT TRI THC KHC MATH2IT tm

1/15/2015 vui:Anhchngchyxe(pn)|Math2IT

http://math2it.blogspot.fr/2014/10/ovuianhchangchayxe.html 2/7

Khi y hai s v c tng bng nn mt trong hai phi nh hn hoc bng . iuny l tt nhin v nu ngc li, c hai s u ln hn th tng ca chng s ln hn .

Xt trng hp c hai cng bng , tc hay . Din dch ra, sau pht k t lc bt u th anh ta i c mt on Km, tha yu cu bi

ton. Chng minh xong.

Trng hp cn li, mt trong hai thng phi nh hn hn v thng cn li tt nhin phi lnhn hn . Mt khc do lin tc nn theo nh l gi tr trung gian, phi c mt gi tr ca (gi l ) . V bi ton c chng minh xong v thi im , sau pht, anh ta li xe i c ng Km.

Th ti tr tu vi chuyn mc vui ca blog Math2IT ti y.

13peoplelikethis.Bethefirstofyourfriends.Like

Dinh Anh Thi : Tc gi blog, xut thn l sinh vin s phm ton, hin ang l nghincu sinh v Ton ng dng ti Php. Chnh v nim am m Ton hc, tin hc ng dngv qua trng lp s phm nn Thi rt quan tm n vic ng dng Ton hc, Tin hcvo trong cuc sng thc t cng nh vic truyn t kin thc Ton cho hc sinh theomt phung php hin i v tch cc nht, gy hng th v hiu su cho ngi hc,ngi c ni chung. Mi chi tit xin lin h dinhanhthimail@gmail.com. Blog c nhnAnh Thi blog.

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9.10.14 , Hiu ton hc vui

Vit bi cng blog bng cch lin h dinhanhthimail@gmail.com.

1/15/2015 vui:Anhchngchyxe(pn)|Math2IT

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vui: Anh chng chy xe (pn)

vui: Cp bin chia tin phinbn 2

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chic my tnh y mnh m

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Ti liu tham kho dnh cho itng t hc LaTeX (cp nht

ngy 6/11/14)

Son tho ton hc trong LaTeX(k 1)

WolframAlpha : gii ton theotng bc

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