Find a particular solution to y4y16sec2tSolutionFirst findin
Find a particular solution to y+4y=16sec(2t).
Solution
First finding auxiliary equation
y\'\'+4y=-16sec(2x)
 =m2+4=0
 m=±2i
C.F.
y=acos2x+bsin2x
now find P.I.
y1=cos2x
 y2=sin2x
 Q= -16sec2x
 W=y1y2\'y2y1\'
So W=2
P.I. =y1(y2*Q)/Wdx+y2(y1*Q)/Wdx
=cos2xsin2x(-8sec2x)dx+sin2xcos2x(-8sec2x)dx
 =8cos2xtan2xdx-8sin2x1dx
 P.I=4cos2x(lnsec2x)-8(sin2x)x

