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Assume the growth rate is x , the eating speed of a sheep is y , and the total grass is T , S sheep eat it in 96 days
24*70y-T-24x=0 (1)
60*30y-T-60x=0 (2)
96*Sy-T-96x=0 (3)
Since , y , T , S , x are unknown , then we can use (1)+(2)=(3) to solve it
since 24+60 is not equal to 96
then we have to solve this 24n+60m=96k & nT+mT=kT , Cuz, n(1)+m(2) = k(3).
Simplified get 2n+5m=8k & n+m=k => 0=2n+m , let n=1 then m=-2 , then k=-1
multiply (1) by n=1 , get 24*70y-T-24x=0
multiply (2) by m=-2 , get -60*60y+2T+120x=0
multiply (3) by k=-1 , get -S*96y+T+96x=0
Note that n(1)+m(2)=-1920y+T+96x=0
Then -96S=-1920, S=20
I know , but when I use w=ylny, I will get a different result , I wanna know why?
Check my calculation above
I have a problem with
, plz tell me how to do it , and tell me where I was wrong.Here what I did,
no doubt about that.I use
That will be
, which is different from the answer.You must be confused by this equality
. that F is the combination of all forcesActually, u imply that k is smaller than n , then n! must contains one k , then k | n! , therefore k | n!+k
I need to solve
I put all the x on one side and the y on the other and integral
but the result comes out different from the answer'
the answer is
Solve the differential equation
I know there is a rule
but if I let
Actually there's a shortcut ~
Yah , I understand .
Because C is a complement of A , and A is a subset of U
I undertand you prove ,
My prove was, like U={1,2,3,4} , Let A be a subset of U , and C be the complement of subset A, then C is also a subset of U,
If A={1,2,3} , then C={4}, if A has all the elements, then C is an empty set.
If U is any random set, then there must be a subset C which is empty.
What I need to prove is , Empty set is the subset of every set.
A is a subset of U , then the complement of A must be a subset of U , since , A has all the elements that are in U , then the complement of A must be an empty , and is in U.
Prove that the empty set is a subset of every set.
If a subset A has all the elements that of the universal Set U , then the complement of subset A is a empty set , then the empty set is in U , then it's a subset of U .
maybe the new vertex are on the bisector of each angle.
Can I use
in 2??Hmmm , If you know the coordinates of three vertex, each side of the new triangle paralells with the old one , that means the slopes are the same, they share the same core.
These are the 3 last questions, the entrance exam just like sat , but only got 120 minute to finish 21 questions.
Yeah , the second is kind of tricky.
I think the Chinese math exam is a little harsh , Since everyone has to deal with problem like these , no matter what your major is.
Two functions
have intersections Point A and O .2. A circle
has intersections with line at point P and Q,These questions come from the 1st pre-test of College Entrance in China.
1.
Cleaned up latex from over running the page - Ricky
Janefairfax's proof is fantastic . I think it can also be solved by geometry , This maybe will give you a hint , ACO is part of a Heptagon , and BA is the extend of AC , CO vertical to BO , and Ao is one side of the Heptagon , length is 1. I didnt actually prove it , but Can this work?
How do I upload picture , I pressed the upload botton , and select my picture but it didnt show.