dfrac (sqrt {3)}(2)sin (15)^circ +dfrac (1)(2)cos (15)^circ 的值为( )A．dfrac (sqrt {3)}(2)sin (15)^circ +dfrac (1)(2)cos (15)^circ B．dfrac (sqrt {3)}(2)sin (15)^circ +dfrac (1)(2)cos (15)^circ C．dfrac (sqrt {3)}(2)sin (15)^circ +dfrac (1)(2)cos (15)^circ D．1

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

=-sqrt (2)(sin dfrac (pi )(6)+icos dfrac (pi )(6))的指数表达式为（ ）。A =-sqr

dfrac (1)(2)-|||-C .dfrac (sqrt {2)}(2)-|||-D .dfrac (sqrt {3)}(2)

[题目]-|||-求曲线 ^dfrac (2{3)}+(y)^dfrac (2{3)}=(a)^dfrac (2{3)} 在点 (dfrac (sqrt {2)

lim _(xarrow 0)dfrac (sin 2x-2sin x)(x(sqrt [3]{1+{x)^2}-1)}..

^circ -dfrac (4)(2)-|||-:^circ +dfrac ({varphi )^1}(2) D. ^circ -dfrac ({varphi

2.求曲线 ^dfrac (2{3)}+(y)^dfrac (2{3)}=(a)^dfrac (2{3)} 在点 (dfrac (sqrt {2)}(4)a,d

2.求曲线 ^dfrac (2{3)}+(y)^dfrac (2{3)}=(a)^dfrac (2{3)} 在点 (dfrac (sqrt {2)}(4)a,d

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

int dfrac (sin x+cos x)(sqrt [3]{sin x-cos x)}dx