We are working on finding the particular solution for the first-order linear constant-coefficient ordinary differential equation:

RCdvP(t)dt+vP(t)=Vicos⁡(ωt)
The new idea is to find the particular solution for the related equation

RCdvPS(t)dt+vPS(t)=Viest
because we expect that this solution is easy to get and it will help to find the particular solution for the original equation.

If you try vPS(t)=Vpest you will find that it will work; you can solve for Vp. In the space provided below write an algebraic expression for Vp in terms of Vi, s, R and C.

To find the particular solution, we substitute the assumed solution vPS(t) = Vpest into the equation RCdvPS(t)dt + vPS(t) = Viest.

Substituting vPS(t) with Vpest and its derivative with Vpes, the equation becomes:

RC(Vpes)dt + Vpest = Viest

Since e^st is a common factor, we can factor it out:

e^st(RCVp + Vp) = Viest

Now, we can divide both sides of the equation by e^st:

RCVp + Vp = Vie

Factoring out Vp on the left side of the equation:

Vp(RC + 1) = Vie

Finally, we can solve for Vp by dividing both sides by (RC + 1):

Vp = Vie / (RC + 1)

So, the algebraic expression for Vp in terms of Vi, s, R, and C is:

Vp = Vie / (RC + 1)