A. B. C.[1/n-1/(n+1)] D.sin(nπ/3)
A.y3=2(y-xy′) B.2xy′=2y C.2xy′=-y3 D.2xy=2y+y3
A.1 B.-1/2 C.0 D.2
A.y=cy1(x)+y2(x) B.y=y1(x)+c2y2(x) C.y=c[y1(x)+y2(x)] D.y=c1y(x)-y2(x)
A.10arctan2-31n2 B.(5/2)π-3 C.10arctan3-3ln3 D.10arctan(1/3)