4.设 =r(cos theta +isin theta ) .求 dfrac (1)(2) 的三角表示.

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

(int )_(dfrac {pi )(4)}^dfrac (pi {2)}dtheta (int )_(0)^cot theta (r)^2cos theta

4.设总体密度函数如下,x1,···,xn是样本,试求未知参数的矩估计.-|||-(1) (x;theta )=dfrac (2)({theta )^2}(th

12.设曲线的极坐标方程为 rho =dfrac (1)(pi )(1-cos theta ), 求曲线在 theta =dfrac (pi )(2) 处的切线

4.设总体密度函数如下,x1,x2,···,xn是样本,试求未知参数的矩估计:-|||-(1) (x;theta )=dfrac (2)({theta )^2}

(int )_(-dfrac {pi )(2)}^dfrac (pi {2)}4(cos )^4theta dtheta =__________________

5.求下列参数方程所确定的函数的导数 dfrac (dy)(dx)-|||-(3) ) x=theta (1-sin theta ) y=theta cos

把复数=((cos dfrac {2pi )(9)+isin dfrac (2pi )(9))}^3转化为三角形式A =((cos dfrac {2pi )(9

(B) sqrt (dfrac {1cos theta )(g)} _ (C) pi sqrt (dfrac {1)(8)} . (D) pi sqrt (df

当theta =dfrac (pi )(4)时，theta =dfrac (pi )(4)____;当theta =dfrac (pi )(4)时，theta