\vecF \cdot \vecr' = (-3\sin t)(-3\sin t) + (3\cos t)(3\cos t) = 9\sin^2 t + 9\cos^2 t = 9(\sin^2 t + \cos^2 t) = 9 - AMAZONAWS 📅 March 6, 2026 👤 scraface Mar 06, 2026