1+5+6+9+4
giup mink
chung minh rang 4+4^3+4^5+4^7+...+4^23 chia het cho 68
chung minh rang 1+3+3^2+3^3+...+3^2000 chia het cho 13
giup mink voi thu 6 mink nop roi
4 + 4^3 + 4^5 + 4^7 + ... + 4^23
= ( 4 + 4^3 ) + ( 4^5 + 4^7 ) +.....+ ( 4^22 + 4^23)
=4( 1+16 ) + 4^5( 1+16 ) +....+ 4^22( 1+ 16 )
=4 x 17 + 4^5 x 17+....+ 4^22 x 17 chia hết cho 68
Câu 2:
1+3+3^2+3^3+....+3^2000
=( 1+3 +3^2 ) + ( 3^3 + 3^4 + 3^5 ) +.....+ ( 3^ 1998 + 3^1999 + 3^2000)
=1( 1+ 3 + 9 ) + 3^3 + ( 1+ 3 + 9 ) +......+ 3^1998+( 1+ 3 + 9 )
= 1 x 13+ 3^3 x 13 +......+ 3^1998 x 13 chia hết cho 13
k mk nha lần sau mk k lại
Câu 1 nha : 4+4^3+4^5+4^7+....+4^23 = (4+4^3)+(4^5+4^7)+....+(4^21+4^23)
= 68 + 4^4.(4+4^3)+....+4^20.(4+4^3) = 68 + 4^4.68 + .... + 4^20.68
=68.(1+4^4+....+4^20) chia hết cho 68
Câu 2 nha 1+3+3^2+...+3^2000 = (1+3+3^2)+(3^3+3^4+3^5)+....+(3^1998+3^1999+3^2000)
= 13 + 3^3.(1+3+3^2)+....+3^1998.(1+3+3^2) = 13+3^3.13+....+3^1998.13
=13.(1+3^3+....+3^1998) chia hết cho 13
Tính nhanh :
1+2+3+4+5+6+7+8+9 .
Ai tick mink mink tick lại nhớ kb luôn nha
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9
= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5
= 10 + 10 + 10 + 10 + 5
= 45
x:5=9 (dư 2) ,x:6=9(dư 5) ,x:8=4(dư 1)
Trả lời rõ ràng hộ mink.
x:5=9 ( dư 2 )
x=9x5+2
x=47
x:6=9 ( dư 5 )
x=9x6+5
x=59
x:8=4 ( dư 1 )
x=4x8+1
x=33
x : 5 = 9 ( dư 2 ) = 9 x 5 + 2 = 47
x : 6 = 9 ( dư 5 ) = 6 x 9 + 5 = 62
x : 8 = 4 ( dư 1 ) = 8 x 4 + 1 = 33
hok tốt
@Huỳnh Khánh Tín bạn sai ở x:6=9 ( dư 5 )
62 là Sai,59 là đúng.
x^4-3x^2+9 phan tick da thuc thanh nhan tu giup mink vs
mink ko hieu lam bai nay
* 2 * 2 *
x 4
__________
4 8 9 * 0
giup mink nha !
175-95:[(2+8.2).9^0+1^9
giup mink voi mik nghi nen ko biet
= 175 - 95 :(18.1+1)
= 175-95 :19
= 175-5
170
30% - 1 1/5 +1,5 X -1/2 =?
GIUP MINK VOI
\(=0,3-\dfrac{6}{5}+\dfrac{1}{5}.\dfrac{-1}{2}\)
\(=0,3-\dfrac{6}{5}-\dfrac{1}{2}\)
\(=0,3-1,2-0,5\)
\(=-1,4\)
\(\dfrac{1}{7}\cdot2\dfrac{1}{3}+\dfrac{5}{2}\cdot\dfrac{3}{7}-\dfrac{59}{6}\cdot\dfrac{1}{7}\)
giup mink nha
\(\dfrac{1}{7}.2\dfrac{1}{3}+\dfrac{5}{2}.\dfrac{3}{7}-\dfrac{59}{6}.\dfrac{1}{7}\)
=\(\dfrac{1}{7}.\dfrac{7}{3}+\dfrac{5}{2}.\dfrac{3}{7}-\dfrac{59}{6}.\dfrac{1}{7}\)
=\(\dfrac{1}{7}.\left(\dfrac{7}{3}-\dfrac{59}{6}\right)+\dfrac{5}{2}.\dfrac{3}{7}\)
=\(\dfrac{1}{7}.\dfrac{-15}{2}+\dfrac{5}{2}.\dfrac{3}{7}\)
=\(\dfrac{-15}{14}+\dfrac{15}{14}\)
= 0
Tinh nhanh:
m)5^1+5^2+5^3+...+5^199+5^200
n)3^0-3^2+3^3-3^4+...+3^2017-3^2018+3^2019-3^2020
o)6+6*9+6*9^2+6*9^3+...+6*9^99
p)(-1)*(-1^2)*(-1^3)*(-1^4)*...*(-1^99)*-(1^100)
Giup minh nhe!
Đặt \(A=5+5^2+5^3+....+5^{199}+5^{200}\)
\(\Leftrightarrow5A=5\left(5+5^2+5^3+....+5^{199}+5^{200}\right)\)
\(\Leftrightarrow5A=5^2+5^3+5^4+....+5^{200}+5^{201}\)
\(\Leftrightarrow5A-A=\left(5^2+5^3+5^4+....+5^{200}+5^{201}\right)-\left(5+5^2+5^3+....+5^{199}+5^{200}\right)\)
\(\Leftrightarrow4A=5^{201}-5\)
\(\Leftrightarrow A=\frac{5^{201}-5}{4}\)