(1)[﹣0.52+(﹣)2﹣|﹣22﹣4|+(2)2×]÷(0.1)2(2)1﹣2+3﹣4+…+(2k﹣1)﹣2k+…﹣2010(3).-七年级数学

题文

(1)[﹣0.52+(﹣2﹣|﹣22﹣4|+(22×]÷(0.1)2
(2)1﹣2+3﹣4+…+(2k﹣1)﹣2k+…﹣2010(3)
题型:解答题  难度:中档

答案

解:
(1)[﹣0.52+(﹣2﹣|﹣22﹣4|+(22×]÷(0.1)2
=(﹣+﹣|﹣8|+×)÷
=(﹣8+3)100,
=﹣500;
(2)1﹣2+3﹣4+…+(2k﹣1)﹣2k+…﹣2010
=1+(1﹣)﹣(3﹣)+3+()﹣(5﹣)+…+(2k﹣1)+()﹣[2k+1﹣]+…﹣(2010+1﹣),
=1+﹣3++3+﹣5++…+(2k﹣1)+﹣(2k+1)+]+…﹣2011+
=(1﹣3+3﹣5+5﹣…﹣2009+2009﹣2011)+(1﹣++++…+++…+),
=﹣2010+(1﹣),
=﹣2009﹣
=﹣2009
(3)++…+++…+),
=