选择题 1. 若有以下结构体定义: struct p { int x; int y; }xy; 则( )是正确的引用或定义。
A: p.x=100;
B: Struct p xy2; xy2.x=100;
C: struct xy2; xy2.x=100;
D: struct p xy2={100};
A: p.x=100;
B: Struct p xy2; xy2.x=100;
C: struct xy2; xy2.x=100;
D: struct p xy2={100};
举一反三
- 分解因式()x()3()y()-()2()x()2()y()2()+()xy()3()正确的是A.()xy()(()x()+()y())()2()B.()xy()(()x()2()﹣()2()xy()+()y()2())()C.()xy()(()x()2()+2()xy()﹣()y()2())()D.()xy()(()x()﹣()y())()2
- 若有以下的说明、定义和语句,则值为31的表达式是: struct wc {int a; int *b; }*p; int x0[]={11,12},x1[]={31, 32}; static struct wc x[2]={100, x0, 300, x1}; p=x;
- 设\(z = u{e^v}\)，\(u = x + y\)，\(v = xy\)，则\( { { \partial z} \over {\partial x}}=\) A: \({e^{xy}}(1 + xy + {y^2})\) B: \({e^{xy}}(1 + xy + {y^3})\) C: \({e^{xy}}(x+ xy + {y^2})\) D: \({e^{xy}}(y+ xy + {y^2})\)
- 微分方程xdy+2ydx=0满足初始条件y｜x=2=1的特解为( ) A: xy2=4． B: xy：4． C: x2y=4． D: 一xy=4．
- 设\(z = u{e^v}\)，\(u = {x^2} + {y^2}\)，\(v = xy\)，则\( { { \partial z} \over {\partial y}}=\)（ ）。 A: \({e^{xy}}({x}y^2 + {x^3} + 2y)\) B: \({e^{xy}}({x^2}y + {x^3} + 2y)\) C: \({e^{xy}}({x}y^2 + {x^3} + 2x)\) D: \({e^{xy}}({x}y+ {x^3} + 2y)\)