- #1
Agrasin
- 69
- 2
I'm brushing up on calculus. I don't see how this derivative works.
x(t) = A cos(ωt - [itex]\varphi[/itex])
v(t) = dx / dt = - Aωsin(ωt + [itex]\varphi[/itex])
I get that the derivative of cosx is -sinx. I get that the omega is brought outside the cos function because of U substitution.
Why does the the minus sign turn into a plus sign?
Btw I saw this on wikipedia: http://en.wikipedia.org/wiki/Simple_harmonic_motion
x(t) = A cos(ωt - [itex]\varphi[/itex])
v(t) = dx / dt = - Aωsin(ωt + [itex]\varphi[/itex])
I get that the derivative of cosx is -sinx. I get that the omega is brought outside the cos function because of U substitution.
Why does the the minus sign turn into a plus sign?
Btw I saw this on wikipedia: http://en.wikipedia.org/wiki/Simple_harmonic_motion