$\frac{d a}{d \mathrm{time}}=\mathrm{a\_angular\_velocity}$ $\frac{d b}{d \mathrm{time}}=\mathrm{b\_angular\_velocity}$ $\frac{d \mathrm{a\_angular\_velocity}}{d \mathrm{time}}=2a+b\frac{d \mathrm{b\_angular\_velocity}}{d \mathrm{time}}=2.0a-2b$ $\mathrm{a\_}=0.5\cos (0.765366864730179\mathrm{time})+0.25\times 1.41421356237310\cos (0.765366864730179\mathrm{time})+0.5\cos (1.84775906502257\mathrm{time})-0.25\times 1.41421356237310\cos (1.84775906502257\mathrm{time})\mathrm{b\_}=0.5\times 1.41421356237310\cos (0.765366864730179\mathrm{time})+0.5\cos (0.765366864730179\mathrm{time})-0.5\times 1.41421356237310\cos (1.84775906502257\mathrm{time})+0.5\cos (1.84775906502257\mathrm{time})$ $\mathrm{error\_A}=(a-\mathrm{a\_})^2\mathrm{error\_B}=(b-\mathrm{b\_})^2\mathrm{RSS}=\mathrm{error\_A}+\mathrm{error\_B}$