Use https://sagecell.sagemath.org/ to run the SageMath code t,y = var('t y'); plot_slope_field(cos(t+y), (t,-5,5), (y,-5,5))
producing the direction field for the ODE \( {y'} = \cos\left({y} + t\right) \).
Let \(y_p\) be the solution to the following IVP. Explain how to use its direction field to approximate the value of \(y_p\) at \(t= -1 \).
\[ {y'} = \cos\left({y} + t\right) \hspace{2em} y( 1 )= -2 \]
Answer:
\[y_p( -1 )\approx -2.0 \]