To represent a set by description (2.4.6.8) requires an analysis process,

To represent a set by description (2.4.6.8) requires an analysis process,

{2,4,6,8}={x|x=2k,1≤k≤4,k∈N}

How many square decimeters is half a square meter

Half square meter is 0.5 square meter, which can be regarded as 1 meter × 0.5 meter. If 1 meter = 10 decimeter and 0.5 meter = 5 decimeter, then 0.5 square meter = 1 meter × 0.5 meter = 10 decimeter × 5 decimeter = 50 square decimeter

1.5 square meters: 20 square decimeters (simplify and calculate the ratio)

1.5 square meters: 20 square decimeters = 150 square decimeters: 20 square decimeters = 150:20 = (150 / 10): (20 / 10) = 15:2 = 15 / 2 = 7.5

If (a + 3) XY | a | is a quaternion of X and y, then the value of a is ()
A. 3B. -3C. 13D. ±4

∵ (a + 3) XY | a | is a binomial of degree four with respect to X and y, | a + 3 ≠ 0, | a | = 3, the solution is a = 3

When x = 2, y = − 12, the value of the quartic monomial XY3 is______ ．

When x = 2, y = − 12, XY3 = 2 × (- 12) 3 = 2 × (- 18) = - 14

If the monomial x ^ m + 3, y ^ 2 and XY ^ n-1 are the same, find the value of M, n

m+3=1
2=n-1
∴m=-2
n=3

1 / 2 - 1 / 2 + 1 / 3 - 1 / 2 + 1 / 4 - 1 / 3 +... + 1 / 100 - 1 / 99
Urgent. Urgent

1 / 2 - 1 / 2 + 1 / 3 - 1 / 2 + 1 / 4 - 1 / 3 +... + 1 / 100 - 1 / 99
=1-1/2+1/2-1/3+1/3-1/4+…… +1/99-1/100
=1-1/100
=99/100

One third minus one half + one fourth minus one third + one fifth minus one fourth, and so on
1-2 / 1 + 1 / 3 minus 1 / 2 + 1 / 4 minus 1 / 3 + 1 / 5 minus 1 / 4 and so on until + 1 / 2008 minus 1 / 2007

Original form
=1-1/2+1/5-1/3+1/3-1/4+1/4-1/5+...+1/2007-1/2008
=1-1/2008
=2007/2008

One percent plus two percent. What's up to ninety-nine percent? Fifteen percent

99X100+(1+99)X99/2=9850

One hundredth plus two hundredths. Up to ninety-nine hundredths!
To the formula! The final results to be converted into fractions! If you can be simple and easy! Fast!

(（1+2+3+4…… +99）*99/2)/100=99/2