mk ghi thiếu !!! đề là ntn : 

so sánh ; (-1) . (-2 ) . (-3) . ... . (-2017) với 0

Lê Quốc Trần Anh  Coordinator 29/11 at 16:54

We have: 

1st,2nd and 3rd,4th row are given.

5th row: 11;12;13;14;15

6th row: 16;17;18;19;20;21

7th row: 22;23;24;25;26;27;28

So their sum is: 22+23+24+25+26+27+28=175

zúng zông ? 

I do not know ???

mk ko biết làm kiểu kia xin bn thông cảm 

B=ab+c+d+bc+d+a+ca+b+d+da+b+cB=ab+c+d+bc+d+a+ca+b+d+da+b+c

C=b+cb+c+d+c+dc+d+a+a+da+b+d+a+ba+b+cC=b+cb+c+d+c+dc+d+a+a+da+b+d+a+ba+b+c

D=c+db+c+d+d+ac+d+a+a+ba+b+d+b+ca+b+cD=c+db+c+d+d+ac+d+a+a+ba+b+d+b+ca+b+c

E=b+db+c+d+a+cc+d+a+b+da+b+d+a+ca+b+cE=b+db+c+d+a+cc+d+a+b+da+b+d+a+ca+b+c

F=b+c+da+c+d+ab+a+b+dc+a+b+cdF=b+c+da+c+d+ab+a+b+dc+a+b+cd

We have :

C+D+E=8C+D+E=8

Applying the AM-GM inequality, we have :

B+C=a+b+cb+c+d+b+c+dc+d+a+a+c+da+b+d+a+b+da+b+c≥4B+C=a+b+cb+c+d+b+c+dc+d+a+a+c+da+b+d+a+b+da+b+c≥4

B+D=a+c+db+c+d+a+b+da+c+d+a+b+ca+b+d+b+c+da+b+c≥4B+D=a+c+db+c+d+a+b+da+c+d+a+b+ca+b+d+b+c+da+b+c≥4

B+E=a+b+db+c+d+a+b+cc+d+a+b+c+da+b+d+a+c+da+b+c≥4B+E=a+b+db+c+d+a+b+cc+d+a+b+c+da+b+d+a+c+da+b+c≥4

(the equalities happen only when a = b = c = d)

⇒3B+C+D+E≥12⇒3B≥4⇒B≥43⇒3B+C+D+E≥12⇒3B≥4⇒B≥43

(the equality happens only when a = b = c = d)

F=ba+ca+da+cb+db+ab+ac+bc+dc+ad+bd+cd≥12F=ba+ca+da+cb+db+ab+ac+bc+dc+ad+bd+cd≥12

(the equality happens only when a = b = c = d)

⇒A=B+F≥12+43=403⇒A=B+F≥12+43=403 

(the equality happens only when a = b = c = d)

hihi

thank you very much !

The area of the square triangle is:

     12.52 = 3012 . 52 = 30

The area of the semicircle is:

      132.132.3,142 = 26533400 = 66,3325132.132.3,142 = 26533400 = 66,3325

The total area of the shaded regions is:

       66,3325 - 30 = 36,33253636

Answer:36