$y={\sin }^{2}(2-3x)$，则$dy=$$\left(\,\,\,\,\,\right)$
$A、$$\sin (4-6x)dx$
$B、{\cos }^{2}(2-3x)dx$
$C、-3\sin (4-6x)dx$
$D、$$-3\sin (4-6x)$
f(x)=(cos )^23x，则f(3x)=(,,,,,)A、-3sin (6x)B、-3sin (18x)C、-9sin (18x)D、-9sin (6x)
20.求不定积分 int ((2)^x+3cos x)dx ()()-|||-A dfrac ({2)^x}(ln 2)-3sin x+C-|||-B ^xln
(B.) y = (1)/(2)x^2e^2x + sin 2x. (C.) y = (x)/(2)(x + 4)e^3x. (D.) y = (x^2co
设 M=int_(-(pi)/(2))^(pi)/(2) (sin x)/(1+x^2) cos^4 x dx，N=int_(-(pi)/(2))^(pi)/(
函数y=3sin x-4cos x是微分方程y^primeprime+y=0的解。A. 对B. 错
设sin (x+2y-3z)=x+2y-3z，证明sin (x+2y-3z)=x+2y-3z.设，证明.
函数f（x）=x-2sin(x)/(2)cos(x)/(2)，则f′（(π)/(3)）=（ ）A. 0B. $\frac{1}{2}$C. $\frac{\sq
14.int(sin x+3cos x)/(2sin x+cos x)dx=____14.$\int\frac{\sin x+3\cos x}{2\sin x+
27.求下列多项式的有理根:1) x^3-6x^2+15x-14; 2) 4x^4-7x^2-5x-1;3) x^5+x^4-6x^3-14x^2-11x-3
下列各函数中哪些是周期函数?对于周期函数, 指出其周期:(1)y=cos(x−2);(2)y=cos 4x;(3)y=1+sin πx;(4)y=x cos x