[填空题]
A particle P moves is a straight li22h( hf,inhlc gs*u o7ne such that itzu5()ant2g pi s displacement x at time t zp(aiun)25 gt $\geq 0$ is given by the differential equation $\dot{x}$=$2 x\left(-t e^{-t^{2}}\right)$ . At time t=0, x=2 .
1. Use Euler's method with step length 0.1 to find an approximation for x when t=0.4 , giving your answer to 4 significant figures.
x(0.4) ≈ (three decimal places)
2. By solving the differential equation, find the percentage error in your approximation for x when t=0.4 .
ϵ≈ %(two decimal places)
