There are 50 story books in the library. Comic books are half of story books. How many comic books are there? 2. The number of libraries is 20 times that of comic books. How many books are there?

There are 50 story books in the library. Comic books are half of story books. How many comic books are there? 2. The number of libraries is 20 times that of comic books. How many books are there?

There are 50 story books in the library. Comic books are half of story books. How many comic books are there?
Answer: 50 * 1 / 2 = 25
The number of libraries is 20 times that of comic books. How many books are there?
Answer: 25 * 20 = 500

There are 250 comic books and story books in the bookstore. If the comic books sell 1 / 9, there will be 5 more comic books than story books

Sequence 2 / 2,4 / 2 ^ 2,6 / 2 ^ 3 ,2n/2^n,…… The sum of the first n terms of=

Sn =2/2 + 4/2² + 6/2³ + …… + 2(n-1)/2^(n-1) + 2n/2^n ………… ①
2Sn=2×(2/2 + 4/2² + 6/2³ + …… + 2n/2^n)
=2 + 4/2 + 6/2² + 8/2³ + …… + 2n/2^(n-1) ………… ②
② Minus 1
Sn=2 + 2/2 + 2/2² + 2/2³ + …… +2/2^(n-1) - 2n/2^n
=2[1-(1/2)^n]/[1-(1/2)] - 2n/2^n
=4 - 4/2^n - 2n/2^n
=4 - (2n+4)/2^n
=4 - (n+2)/2^(n-1)
This is called dislocation subtraction

Logarithm and exponent
1. It is known that a = log6 (27) and a denotes log18 (16)
2. Given 3 * a = 5 * b = C and (1 / a) + (1 / b) = 2, find the value of C
If you can't type the subscript, just look around. In the first question, the real number is in brackets,

1. A = log6 (27) = lg27 / LG6 = 3lg3 / (LG2 + Lg3) 3lg3 = a (LG2 + Lg3) Lg3 = alg2 / (3-A) log18 (16) = LG16 / LG18 = 4lg2 / (LG2 + 2lg3) = 4lg2 / [LG2 + 2alg2 / (3-A)] = 4 / [1 + 2A / (3-A)] = 4 (3-A) / (3 + a) 2.3 ^ a = 5 ^ B = C. taking the logarithm of base 10, we get alg3 = blg5 = LGCA = L

Enter two positive integers m and n (M and N are represented by long integers) and calculate their greatest common divisor
#include"stdio.h"
main()
{
\x05long m,n,c;
\x05scanf("%d%d",&m,&n);
L1:if(m==n) goto L2;
if(m

#include
//Rolling method
int gcd(int a,int b)
{
\x05int c,d;
\x05if (a

From the third paragraph of the Three Gorges, find out the sentences that describe the scenery of the Three Gorges in color and dynamic
In color:
Dynamically:

Color: spring and winter, then plain turbulence green pool, back to clear reflection
Dynamic: Juezi more strange cypress, hanging spring waterfall, flying gargle between

Why is the equivalent infinitesimal of 1-cosx * 2 x * 4 / 2

Because the equivalent infinitesimal of 1-cosx is X & # / 2
This is cosx & # 178;
So it's (X & # 178;) &# 178 / 2 = x & # 8308 / 2

There are 102 students in two classes of grade 6 in a school. If 1 / 18 of the total number of students is transferred from Class A to class B, the number of students in the two classes is the same
How many people are there in class a? (detailed description)

102÷【（1 - 1/18 ）×2】
= 102 ÷ 17/9
=Class A for 54

1. 15 is 1 / 4 more than () and () is 2 / 7 less than 35. 2. 27 meters in 10 is equal to () meters () decimeters. When 21 / 4 is equal to what time

15 is 1 / 4 more than (12); (25) is 2 / 7 less than 35; 2 / 10 27m is equal to (2) m (7) decimeter; 21 / 4 is equal to 5:15

If the sequence {an} satisfies 3an + 1 + an = 0, A2 = - 43, then the sum of the first 10 terms of {an} is equal to______ ．

∵ 3an + 1 + an = 0 ∵ an + 1An = − 13, ∵ sequence {an} is an equal ratio sequence with - 13 as the common ratio ∵ A2 = - 43, ∵ A1 = 4. From the summation formula of equal ratio sequence, S10 = 4 (1 − (− 13) 10) 1 + 13 = 3 (1-3-10). So the answer is: 3 (1-3-10)