图示长0.5m，边长的正方形截面大柔度杆，承受轴向压力，弹性模量，则该杆的工作安全系数至少为：=2sqrt (3)times 10mm=2sqrt (3)times 10mm=2sqrt (3)times 10mm=2sqrt (3)times 10mm

-3sqrt (2) C. -2sqrt (3) D. -1

=2sqrt (2) D. Delta PAC 的面积为 sqrt (3)

(int )_(1)^sqrt (3)dfrac (dx)({x)^2sqrt (1+{x)^2}};

求下列定积分:-|||-(10) (int )_(1)^sqrt (3)dfrac (dx)({x)^2sqrt (1+{x)^2}}

(16) (int )_(1)^sqrt (3)dfrac (dx)({x)^2sqrt (1+{x)^2}};

3.复数sqrt (2)+2sqrt (2)i的三角表达式（）3.复数的三角表达式（）A.B.C.D.

.计算下列定积分:-|||-(10) (int )_(1)^sqrt (3)dfrac (dx)({x)^2sqrt (1+{x)^2}}

将根式化为指数形式dfrac ({x)^2sqrt (x)}(sqrt [3]{x)}=将根式化为指数形式

已知(sin )^2theta -(cos )^2theta =dfrac (2sqrt {2)}(3)，求(sin )^2theta -(cos )^2the

计算下列各题：（1）sqrt((1)/(4))×sqrt(144)；（2）3sqrt(2)×5sqrt(8)；（3）5sqrt(x)•6sqrt((x)^3)；