发布网友 发布时间:2024-10-23 16:54
共3个回答
热心网友 时间:2024-11-09 10:33
作P1⊥X轴于D1,P2⊥X轴于D2……Pn⊥X轴于Dn,
则有x1=y1,x2=y2,……xn=yn;
x1=y1,x1*y1=9==>x1=y1=3==>OA1=2x1=6
==>(A2D2+OA1)*P2D2=9
<==>(x2+6)*y2=9,x2=y2
<==>(x2+6)*x2=9==>x2^2+6x2-9=0-->x2=-3+3√2(负值已舍去)
-->A1A2=2x2=-6+6√2;
==>(A3D3+OA2)*P3D3=9
<==>(x3+6-6+6√2)*y3=9,x3=y3==>(x3+6-6+6√2)*x3=9
-->x3^2+(6√2)x3-9=0==>x3=-3√2+3√3(负值已舍去)
-->A2A3=2x3=-6√2+6√3;
==>(A4D4+OA3)*P4D4=9
<==>(x4+6-6+6√2-6√2+6√3)y4=9,x4=y4
==>(x4+6√3)x4=9==>x4=-3√3+6=-3√3+3√4(负值已舍去)
-->A3A4=2x4=-6√3+6√4
…………
-->A(n-2)A(n-1)=-6√(n-2)+6√(n-1)
<-->x(n-1)=y(n-1)=[A(n-2)A(n-1)]/2=-3√(n-2)+3√(n-1);
==>A(n-1)An=-6√(n-1)+6√n
-->xn=yn=[A(n-1)An]/2=-3√(n-1)+3√n
<-->:
y1+y2+y3+y4+……+y(n-1)+yn
=3+(-3+3√2)+(-3√2+3√3)+(-3√3+3√4)+……+[-3√(n-2)+3√(n-1)]+[-3√(n-1)+3√n]
=3√n
热心网友 时间:2024-11-09 10:40
无图无解
热心网友 时间:2024-11-09 10:39
gfd