2.4.3 ode is Integrable as given

2.4.3.1 Example 1
2.4.3.2 Example 2

ode internal name "second_order_integrable_as_is"

This is the same as "exact_nonlinear_second_order_ode". Can be linear or nonlinear. But must be of degree one. ODE is integrable as is w.r.t. the independent variable \(x\).  Need to merge type names into one.