differential inhomogenous????help

• Apr 21st 2008, 11:45 AM
i_zz_y_ill
differential inhomogenous????help
y2+(7/m)y+(5/m)=0 (auxiliary eqn) where m=2.45=49/2
k so used quadratic formula get one realroot 20/14

so (complementary eqn) x=Ae^1.43t displacement time btw

prior to a.e have x''+(7/m)x'+(5/m)x=g g=10ms^-2

therefore to consider g do trial x = y
5y/m 10
y = 4.9
therefore x = Ae^1.43t + 4.9

FROM HERE IM STUCK

answer is x = 4.9 - (7.01t + 4.9)e^-1.43t
if n e onecan ee if ive gone wrong ,,,or show me wht t do now that'd be gr8 cheers!!!
• Apr 21st 2008, 01:33 PM
topsquark
Quote:

Originally Posted by i_zz_y_ill
y2+(7/m)y+(5/m)=0 (auxiliary eqn) where m=2.45=49/2
k so used quadratic formula get one realroot 20/14

so (complementary eqn) x=Ae^1.43t displacement time btw

prior to a.e have x''+(7/m)x'+(5/m)x=g g=10ms^-2

therefore to consider g do trial x = y
5y/m 10
y = 4.9
therefore x = Ae^1.43t + 4.9

FROM HERE IM STUCK

answer is x = 4.9 - (7.01t + 4.9)e^-1.43t
if n e onecan ee if ive gone wrong ,,,or show me wht t do now that'd be gr8 cheers!!!

Well something really IS screwy because I'm not getting a real solution to your auxiliary equation for that value of m.

-Dan