[题目] (sin )^2x+(cos )^2x= __

[题目]如果 (cos x)=dfrac ({sin )^2x}(cos 2x), 则 f(x)= () )-|||-

[题目] lim _(xarrow 0)(dfrac (1)({sin )^2x}-dfrac ({cos )^2x}({x)^2})= __

[题目]求 lim _(xarrow 0)(dfrac (1)({sin )^2x}-dfrac ({cos )^2x}({x)^2})

[题目]求 lim _(xarrow 0)(dfrac (1)({sin )^2x}-dfrac ({cos )^2x}({x)^2})

cos 2x(e)^-x+ sin 2x(e)^-xdx-|||-B.cos2xe^(-x)- sin 2x(e)^-xdx-|||-. cos 2x(e)^

sin^2x+cos^2x=_____$$sin^2x+cos^2x=$$_____

lim _(xarrow 0)dfrac (ln ({sin )^2x+(e)^x)-x}(ln ({x)^2+(e)^2x)-2x}

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

求下列不定积分:-|||-(22) int dfrac (cos 2x)({cos )^2x(sin )^2x}dx ;

int dfrac (cos 2x)(cos x+sin x)dx