(3) 'sin x=yln y ,|x=dfrac (pi )(2)=e;

( (int )_(dfrac {pi )(4)}^dfrac (pi {3)}dfrac (x)({sin )^2x}dx ;

设(x)=sin x, 则(dfrac (pi )(2))= __-|||-_.-|||-A cos dfrac (pi )(2)-|||-B o-|||-C-

(9) (int )_(-dfrac {pi )(2)}^dfrac (pi {2)}|sin x|arctan (e)^xdx

(int )_(-dfrac {pi )(2)}^dfrac (pi {2)}dfrac (|x|sin x)(1+{cos )^3x}dx=(int )_(-

(sin x)=dfrac (1)({cos )^2x} in (0,dfrac (pi )(2)),则(sin x)=dfrac (1)({cos )^2x}

(2) dfrac (dy)(dx)=yln dfrac (y)(x);

设(X,Y)的分布函数为(x,y)=dfrac (1)({pi )^2}(dfrac (pi )(2)+arctan dfrac (x)(2))(dfrac (

计算 lim _(xarrow dfrac {pi )(2)}dfrac (ln sin x)({(pi -2x))^2}

求lim _(xarrow dfrac {pi )(2)}dfrac (ln sin x)({(pi -2x))^2}求

例8】(2022,数三)已知函数 (x)=(e)^sin x+(e)^-sin x, 则 (2pi )= __