Tính nhanh
M = 1 -2 -3 + 5 - 6 +8 + ... + 1993 - 1994 - 1995 + 1996 + 1997
Tinh nhanh: M=1-2-3+4+5-6-7+8+...+1993-1994-1995+1996+1997
Tính nhanh: M=1-2-3+4+5-6-7+8+...+1993-1994-1995+1996+1997
(1-2-3+4)+(5-6-7+8)+.....+(1993-1994-1995+1996)+1997
=0+0+....+0+1997
=1997
Tính nhanh:
M=1-2-3+4+5-6-7+8+...+1993-1994-1995+1996+1997
Tính nhanh
M = 1 - 2 -3 + 4 + 5 - 6 +8 ... + 1993 - 1994 - 1995 + 1996 + 1997
XIN CẢM ƠN !
HU HU , Giúp mình với , ngày mai mình phải nộp rồi !
M= 1-2-3+4+5-6-7+8+...........+1993-1994-1995+1996+1997.
Tinh nhanh:
1-2-3+4+5-6-7+8+.........1993-1994-1995+1996+1997
a,x-10/1994+x-8/1996+x-6/1998+x-4/2000+x-2/2002=x-2002/2+x-2000/4+x-1998/6+x-1996/8+x-1994/10
b,x-1991/9+x-1993/7+x-1995/5+x-1997/3+x-1999/1=x-9/1991+x-7/1993+x-5/1995+x-3/1997+x-1/1999
c,x-1/13-2x-13/15=3x-15/27-4x-27/29
N=2000+1999-1998-1997+1996+1995-1994-1993+..........-6-5+4+3-2-1
giúp tuiiiiii với
=0+0+.......+0+2000
=2000
mik chỉ bt thế thui
a) A=1-2-3+4+5-6-7+.....+1996+1997-1998-1999+2000
b) B=1-3+5-7+....+2001-2003+2005
c) C=1-2-3+4+5-6-7+8+.....+1993-1994-1995+1996+1997
d) D=1000+998+996+......+10-999-997-995-...-11
a) A=1-2-3+4+5-6-7+.....+1996+1997-1998-1999+2000
=(1-2-3+4)+(5-6-7+8)+...+(1997-1998-1999+2000)
=0
b) B=1-3+5-7+....+2001-2003+2005
=(1-3)+(5-7)+...+(2001-2003)+2005
=-2.501+2005
=-1002+2005
=1003
c) C=1-2-3+4+5-6-7+8+.....+1993-1994-1995+1996+1997
=(1-2-3+4)+(5-6-7+8)+...+(1993-1994-1995+1996)+1997
=1997
d) D=1000+998+996+......+10-999-997-995-...-11
=(1000-999)+(998-997)+(996-995)+....+(12-11)+10
=1.495+10
=595