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3x ＞ 2x mathematical inequality
3x＞2x
Obviously, x > 0 is enough
How to calculate 4.9 △ 14
4.9÷7÷2=0.35
Can 2010 square plus 2010 be divided by 2010
(2010 ^ 2 + 2010) / 2010 = 2010 + 1 = 2011 can be divisible
Solution equation: 3x-8x-20 = 15x-35 + 4
3x-8x-20=15x-35+4
3x-8x-15x=20-35+4
-20x=-11
x=11/20
5. For a section of railway, it is necessary to replace each 12 meter long new rail with the original 6 meter long old rail. This section of railway has 84 old rails. How many new rails are needed?
Please list the formula
6. To pave a room with a length of 4 meters and a width of 3 meters, we need to use 48 square bricks. If we want to pave a multifunctional classroom with a length of 18 meters and a width of 12 meters, how many square bricks should we use?
Please list the formula
5.
84 * 6 / 12 = 42
six
48 * (18 * 12) / (4 * 3) = 864 pieces
The limit of absolute value of sequence {an} is 0, and the limit of sequence {an} is also 0. How to prove that the two are necessary and sufficient conditions for each other
Using | an-0 | = | an | - 0 |, combined with the definition of limit
For the sequence {an}, if there is a constant a, no matter how small a positive number m is specified in advance, a term an can be found in the sequence, so that the absolute value of the difference between all the terms after this term and a is less than m, (that is, | an-a when n > n)|
-2004² 2005² -2006² 2007²…… What's number n?
(-1)^n*(2003+n)^2
Simple calculation: 1 and 1 / 2-5 / 6 + 7 / 12-9 / 20 + 11 / 30-13 / 42 (important process)
1 and 1 / 2-5 / 6 + 7 / 12-9 / 20 + 11 / 30-13 / 42
=(1+1/2)-(1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)
=1+1/2-1/2-1/3+1/3+1/4-1/4-1/5+1/5+1/6-1/6-1/7
=1-1/7
=6/7
Solving the differential equation of unknown general solution y '= C1 * e ^ (C2)
To solve the differential equation with known general solution y = C 1 * e ^ (XC 2)
LNY = lnc1 + XC2, y '/ y = C2,
The differential equation YY '' = (y ') ^ 2 is obtained by further deriving on both sides, [y' - Y - (y ') ^ 2] / y ^ 2 = 0
What is the solution set of inequality x + 1 greater than or equal to 0
x+1≥0
x≥-1
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