17da4243ce1def6.jpg=3sin(314t+50°), [img=10x17]17da4243d8849cc.jpg[/img]=-4sin(314t+95°)A的[img=10x17]17da4243ce1def6.jpg[/img]与[img=10x17]17da4243d8849cc.jpg[/img]的相位差[img=46x16]17da4243eaddf12.jpg[/img]是
A: 45°
B: -45°
C: 135°
A: 45°
B: -45°
C: 135°
举一反三
- 17da4243ce1def6.jpg=2sin（314t+10°）A与[img=10x17]17da4243d8849cc.jpg[/img]=-4sin（314t+95°）A的相位差[img=15x14]17da426d14450d1.jpg[/img]－[img=15x14]17da426d1dc5113.jpg[/img]是 A: 95° B: ﹣85° C: 85°
- 求不定积分[img=132x48]17da6537fc8dad6.png[/img]； （ ） A: -(4*(cos(x/2)/2 + 2*sin(x/2)))/(17*exp(2*x)) B: (4*(sin(x/2)/2 + 2*sin(x/2)))/(17*exp(2*x)) C: (4*(cos(x/2)/2 + 2*sin(x/2)))/(17*exp(2*x)) D: (4*(cos(x/2)/2 + 2*cos(x/2)))/(17*exp(2*x))
- 求微分方程[img=143x21]17da5f14490e50e.png[/img]的通解,实验命令为(). A: dsolve(D2y-2*Dy+5*y=sin(2*x),x)ans =exp(x)*sin(2*x)*C2+exp(x)*cos(2*x)*C1+1/17*sin(2*x)+4/17*cos(2*x) B: dsolve('D2y-2*Dy+5*y=sin(2*x)','x')ans =cos(2*x)*(sin(4*x)/17 - cos(4*x)/68 + 1/4) - sin(2*x)*(cos(4*x)/17 + sin(4*x)/68) + C1*cos(2*x)*exp(x) - C2*sin(2*x)*exp(x) C: dsolve(D2y-2*Dy+5*y=sin(2*x),'x','y')ans =exp(x)*sin(2*x)*C2+exp(x)*cos(2*x)*C1+1/17*sin(2*x)+4/17*cos(2*x)
- A,B,C为相互独立的三个事件,若[img=171x21]17da55ab2ed8999.png[/img],则[img=84x21]17da55ab49b3232.png[/img]的值为 A: 1/2 B: 10/17 C: 3/10 D: 6/17
- A,B,C为相互独立的三个事件,若[img=171x21]17e0a9054bd2e40.png[/img],则[img=84x21]17e0a90593d7e36.png[/img]的值为 A: 1/2 B: 10/17 C: 3/10 D: 6/17