So sanh :
A = 1/2 + 1/4+ 1/8 + 1/16 + 1/32 voi 2005/2006
so sanh: A=2005^2005+1/2005^2006+1va B=2005^2004+1/2005^2005+1
so sanh:1/2+1/4+1/8+1/16+............+1/512 voi 1
so sanh A va B
A= (2+1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)
B=2^32
Ax(2-1)=(2-1)(2+1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)=(2^2-1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)=(2^4-1)(2^4+1)(2^8+1)(2^16+1)=(2^8-1)(2^8+1)(2^16+1)=(2^16-1)(2^16+1)=2^32-1
Vậy A=B
Áp dụng hằng đẵng thức A^2-B^2 đó bạn
a,tính tổng : \(S=\dfrac{27+4500+135+550+2}{2+4+6+...+14+16+18}\)
b, So sánh : \(A=\dfrac{2006^{2006}+1}{2006^{2007}+1}v\text{à }B=\dfrac{2006^{2005}+1}{2006^{2006}+1}\)
- Mình dùng cách lớp 8 để làm câu b được không :)?
- Tham khảo câu b:
https://olm.vn/hoi-dap/tim-kiem?q=+++++++++++A=2006%5E2005+1/2006%5E2006+1B=2006%5E2006+1/2006%5E2007+1so+s%C3%A1nh+A+v%C3%A0+B&id=520258
A=20052005+1/20052006+1 : B=20052004+1/20052005+1
so sanh A va B
TINH NHANH
CHO M= 22+22+23+24+...+21975
HAY SO SANH M VOI 21975
CHO B =1+2+22+23+...+22005
A =22006-1
HAY SO SANH A VOI B
1 a, 3 va 1/5 - 2 va 1/6 + 1/5
b, 5 va 12/13 - 2 va 15/26 + 1/26
c, 7 va 1/12 + 1/12 - 6 va 1/4
2 tinh gia tri bieu thuc
a, 3 va 2/9 - [1 va 5/8 + 1 va 2/9 ] - 3/8
b, 4 va 2/5 - 1 va 3/7 - 1 va 4/7 + 1/5
c, 1 va 9/12 - 5/4 - 1/2
3 tinh
a, 6 nhan 7 nhan 8 nhan 9 nhan 1 tren 18 nhan 16 nhan 14 nhan 12 nhan 2
b, 4 nhan 15 nhan 9 nhan 24 tren 3 nhan 12 nhan 8 nhan 5
4 rut gon cac phan so
a, 96/150 ; 255/408 ; 630/224
b, 1515/1717; 352352/470470; 200620062006/200520052005
5 so sanh cac phan so
a, 7/9 va 9/7 ; b, 135/120 va 13/8; c, 3535/4848 va 5/8 ; d, 650650/480480 va 222222/144144
6, so sanh hai phan so
a, 2005/2006 va 2006/2007 ; b, 2008/2007 va 2007/2006
cac ban lam tung buoc nha
A=(1/4-1).(1/9-1).(1/16-1)......(1/400-1) . so sanh A voi -1/2
so sanh hai so a=332-1
b=(3+1)(32+1)(34+1)(38+1)(316+1)
B=\(\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
=>B=\(\left(3+1\right)\left(3-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
=>B=\(\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
=>B=\(\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
=>B=\(\left(3^8-1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
=>B=\(\left(3^{16}-1\right)\left(3^{16}+1\right)=3^{32}-1\)
vậy B=\(3^{32}-1\)
chúc bạn hcoj tốt ^^