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lilMissMindset
 3 years ago
this one is tricky. help please!
y''4y'+3y=2cosx+4sinx
i'm having trouble getting the Yp!
lilMissMindset
 3 years ago
this one is tricky. help please! y''4y'+3y=2cosx+4sinx i'm having trouble getting the Yp!

This Question is Closed

him1618
 3 years ago
Best ResponseYou've already chosen the best response.2You can try substituting y = asinx + bcosx

ChmE
 3 years ago
Best ResponseYou've already chosen the best response.0why would that help. I'm in diff eq as well and I wasn't thinking about that.

him1618
 3 years ago
Best ResponseYou've already chosen the best response.2its called th method of undetermined coefficients

him1618
 3 years ago
Best ResponseYou've already chosen the best response.2put it on the left side....compare with coeffs on the right fr etermining a a and b

lilMissMindset
 3 years ago
Best ResponseYou've already chosen the best response.0isn't it y=a cos x + b sinx + cx cos x + dx sin x

him1618
 3 years ago
Best ResponseYou've already chosen the best response.2that is for a special case i think

lilMissMindset
 3 years ago
Best ResponseYou've already chosen the best response.0what are the roots anyway? +i, i aren't they like, twice? then it will be case 4?

ChmE
 3 years ago
Best ResponseYou've already chosen the best response.0r^2  4r +3 = 0 (r  3)(r1) r= 3, 1

lilMissMindset
 3 years ago
Best ResponseYou've already chosen the best response.0that is for the homo part

him1618
 3 years ago
Best ResponseYou've already chosen the best response.2im telling you take y=asinx + bcosx substitute y'' and y' and y in the above eqn and compare LHS and RHS ull get 2 eqns in a and b determine a and b and you have your soln

lilMissMindset
 3 years ago
Best ResponseYou've already chosen the best response.0i did that, i always get 0 for B. it's not supposed to be the answer.

him1618
 3 years ago
Best ResponseYou've already chosen the best response.2im getting the answer as b=1, a=0 which means y=cos x y=cos x satisfies the above eqns

lilMissMindset
 3 years ago
Best ResponseYou've already chosen the best response.0oh sorry. i looked at the wrong answer on my book. i am sorry. Our answer is right. Thank you!
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