Application of a second order differential equation

[pre2grk]

Thanks for posting this video. At end you obtained the solution (at time 9.27). But how to use the solution further to my problem. I know delta, k (=128) and F magnitudes. For time, t = 10 seconds, if I substitute all the values, I get sin(kt) = sin(1280) = -0.342. Is this approach of directly calculating the sin value is correct? I assume kt product is in degrees, is this assumption is valid or kt product should be in radians.

[Teafan123]

@pre2grk In calculus all trigonmetric functions must be evaluated in radians.

[gvsfgdf]

nice.......