## 8 thoughts on “3.43”

1. Trey Hicks says:

In the very last step when you are solving for the x(t) for all three velocities, which equation are using to find the qdot1(0) and qdot2(0)? It doesn't show which equation you are using to get these initial velocities.

1. tutorpaul says:

I used $\dot Q_0 = {A^\star}^T M \dot X_0$. This equation was given toward the bottom left of the page in red.

2. price.hernandez23 says:

Are you sure the x1(t) and x2(t) in part 'a' and 'b' are correct? I get a different answer for the constant being multiplied to the cosine term.

1. tutorpaul says:

(Sorry for not responding to this earlier, I just saw it today.) I'm not certain that my work is correct, but I'm confident it in. What did you get for the coefficient of cosine?

3. seguntytler says:

I think you made a mistake on q2(t), it should be q2(t) = (q2_dot(0)/wn_2) *sin(wn2t)

4. Taylor Glenn says:

at 7:45 in the video when you take the determinant of that matrix you get Lambda 1 = 0, and Lambda 2 = 100, not Lambda 2 = 300. If all you have to do is take the determinant and solve for lambda at that part then i am pretty confident that what i got is correct, but if i am missing a step then please let me know

1. Taylor Glenn says:

Never mind. i forgot a negative sign before i even started to solve it which is why i didn't catch the error