计算12+34+78+…+10231024(x+0.5):212=(x-4):14.-数学

题目简介

计算12+34+78+…+10231024(x+0.5):212=(x-4):14.-数学

题目详情

计算
1
2
+
3
4
+
7
8
+…+
1023
1024
(x+0.5):2
1
2
=(x-4):
1
4
题型:解答题难度:中档来源:不详

答案

(1)class="stub"1
2
+class="stub"3
4
+class="stub"7
8
+…+class="stub"1023
1024

=1-class="stub"1
2
+1-class="stub"1
4
+1-class="stub"1
8
+…+1-class="stub"1
1024

=1+1+1+…+1-(class="stub"1
2
+class="stub"1
4
+class="stub"1
8
+…+class="stub"1
1024
),
=10-(1-class="stub"1
2
+class="stub"1
2
-class="stub"1
4
+class="stub"1
4
-class="stub"1
8
+…+class="stub"1
512
-class="stub"1
1024
),
=10-(1-class="stub"1
1024
),
=10-1+class="stub"1
1024

=9class="stub"1
1024


(2)(x+0.5):2class="stub"1
2
=(x-4):class="stub"1
4

2class="stub"1
2
×(x-4)=class="stub"1
4
×(x+0.5),
2class="stub"1
2
x-10=class="stub"1
4
×(x+class="stub"1
2
),
2class="stub"1
2
x-10=class="stub"1
4
x+class="stub"1
8

(2class="stub"1
2
-class="stub"1
4
)x=10class="stub"1
8

class="stub"9
4
x=class="stub"81
8

x=class="stub"81
8
×class="stub"4
9

x=class="stub"9
2

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