以下程序中，正转接触器Y0与启动按钮X0的逻辑关系是：LD X0OUT Y0 A: X0=0则Y0=1 B: X0=0则Y0=0 C: Y0始终为0 D: Y始终为1

设F(x,y,z)具有连续的偏导数，F(x0,y0,z0)=0，则满足下列哪个条件时可由方程F(x,y,z)=0确定二元函数z=f(x,y) A: Fx(x0,y0,z0)≠0 B: Fy(x0,y0,z0)≠0 C: Fz(x0,y0,z0)≠0 D: Fz(x0,y0,z0)=0

下列Matlab代码，能求解微分方程 y'(t) = 2*t , y(0) = 1的是( ) A: tspan = [0 5];<br> y0 = 0;<br> [t,y] = ode45(@(t,y) 2*t, tspan, y0); B: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*t, tspan, y0); C: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*y, tspan, y0); D: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*t*y, tspan, y0);

设F(x，y)具有二阶连续偏导数，且F(x0，y0)=0，F"x(x0，y0)=0，F"y(x0，y0)＞0．若一元函数y=y(x)是由方程F(x，y)=0所确定的在点(x0，y0)附近的隐函数，则x0是函数y=y(x)的极小值点的一个充分条件是 A: F"xx(x0，y0)＞0． B: F"xx(x0，y0)＜0． C: F"yy(x0，y0)＞0． D: F"yy(x0，y0)＜0．

【填空题】void Bresenham_line(CDC *pDC, int x0, int y0, int x1, int y1, long color) { int dx = abs(x1 - x0); int dy = abs(y1 - y0); int x = x0; int y = y0; int stepX = 1; int stepY = 1; if() //从右向左画 stepX = -1; if() stepY = -1; if() //沿着最长的那个轴前进 { int e = (); for(int i=0; i<=dx; i++) { pDC->SetPixel(x, y, color); x += (); e += (); if(e >= 0) { y += stepY; e -= dx; } } } else { int e = 2 * dx -