Math problems, speed give extra points!!

Solution: 1. EF=3 can be obtained from the area formula, and EA= is known from the question, so t=.

2. If BF is at right angles to CE, and the focus is point 0, then the triangle BOC is an isosceles right triangle, and the distance from the point O to the BC line is equal to half of the BC is 3cm, so the distance from O to EF is 1cm, and the same triangle OEF is also an isosceles right triangle, EF BC=1 3 gets EF=2cm, so EF moves 2cm each, so T = 1 second.

3. Impossible, when boc=120°, at this time abe=60° because ab=cd=4, ae=ab*tan ab=abtan60°=4 3 ad=6, and when e moves to point d, it stops, so according to the title ae =ad=6, so it contradicts the title, so it does not exist.

1) (6+6-4t)*4 2=18 or (6+4t-6)*4 2=18t= or t=

Yes bcfe t = rounded.

2) Both e and f are constant velocity.

The quadrilateral EBCF is an isosceles trapezoid.

BF = CE over F to make EC parallel lines and BC extension lines at G BFG=90°CG=EF

cd=1/2bg

6+(6-4t)=2*4 or 6+(4t-6)=2*4t=1 or t=2

is BCFE t=2 rounds.

3) No, you can't. O to do AD perpendicular line to H, CB to i, E to do CB perpendicular line to J Boc = 120° isosceles trapezoidal FBCE EJ=4 EBJ = 30°

bj = ae = 2t = 4 root number 3

t = 2 root number 3

2*2 root number 3 6

No. If it's hard to understand, it's better to draw a picture.

Let the hundred digit be x

Then the two-digit number composed of ten digits and single digits is 9x+3, and the original number is 100x+9x+3

When you move to the far right, the number 10 becomes 100 digits, and you become 10 digits, both magnified by a factor of 10.

So the number becomes 10*(9x+3)+x

Since the question is set up: 10*(9x+3)+x+45=100x+9x+3, so 91x+75=109x+3

18x=72 so x=4

Then the two-digit digit number of ten and single digits is 39

So the number is 439

Thank you n n

One: Every time is 1+++300, now it's a matter of how many times to complete: the next time is the sum of every 2 numbers, and the number of the first answer is less than half, the first time there are 300 numbers, the second time to finish 150 numbers, the third time to finish 75 numbers, but at the beginning of the 4th time, the next number will be used, but it does not affect the result, so there are 38 numbers after the 4th time, 19 numbers after the 5th time, 10 numbers for the 6th time, and 5 numbers for the 7th time, There are 3 in the 8th finish, 2 in the 9th finish, and 1 number in the 10th, so the result is (1+300)*300 2*10=451500

2: (root number 3 times a + b) divided by (root number cover liquid 2 times b + a) is a rational number, then, we let this rational number be k, then a and b have a Liang Hui relation, but c does not have any relationship with a and b, I think the question is wrong.