cho 4 so : 12 ; 15 ;a ; va 18 . tim so a biet a bang trung binh cong cua 4 so .
cho 4 so 12, 15, 21 va a . tim so a biet so a = trung binh cong cua 4 so 12 , 15 , 21 ,va a
Cho 4 so 12 15 21 va a . Tim so a biet so a bang trung binh cong 4 so 12 15 21 va a
tim so a ....
Cho 4 số 12, 15, 21 và a. Tim a biet so a bang trung binh cong cua 4 so 12, 15, 21 va a
cho 4 so 12,15,21va a tim so a biet so a bang trung binh cong cua 4 so 12 ,15 ,21
so co 4 chu so chia het cho 2 3 4 6 8 12
so chia het la so :
ta nhan thay : 2 x 12 = 24 ;8 x 3 =24 ; 6 x 4 = 24
vay so can tim la 24
Cho 4 chu so: 3;5;7 va X. Voi 4 chu so da cho nguoi ta lap duoc 12 so, moi so co 4 chu so va co du mat 4 chu so da cho. Tim chu so X
Nho trinh bay nghe may ban
cho phan so 3 4 neu cong them 12 vao tu so thi can phai cong them bao nhieu vao mau so de duoc phan so moi bang 3 4
cho 4 so 80 90 a va b hoi a nho hon b biet so a nho hon so tbc cua 3 so 80,90,a la 4 so b lon hon tbc cua 4 so la 12
Cho S = 4^0 + 4^1 + 4^2 + 4^3 +...+ 4^35Hãy so sánh 3S với 64^12
\(4^0+4^1+4^2+4^3+...+4^{35}\\ 4S=4^1+4^2+4^3+4^4+...+4^{36}\\ 4S-S=\left(4^1+4^2+4^3+4^4+...+4^{36}\right)-\left(4^0+4^1+4^2+4^3+...+4^{35}\right)\\ 3S=4^{36}-1=64^{12}-1\\ Vì64^{12}-1< 64^{12}\\ \Rightarrow3S< 64^{12}\)
Ta có: \(64^{12}=\left(4^3\right)^{12}=4^{36}\)
\(S=4^0+4^1+...+4^{34}+4^{35}\)
\(\Rightarrow4S=4^1+4^2+...+4^{35}+4^{36}\)
\(\Rightarrow4S-S=4^{36}-4^0\)
\(\Rightarrow3S=4^{36}-1< 4^{36}\)
Vậy \(3S< 64^{12}\)