Final answer:
The RK4 method requires four function evaluations in each step when solving an initial value problem.
Step-by-step explanation:
The fourth-order Runge-Kutta (RK4) method is a numerical method used to solve initial value problems in differential equations. In each step of the RK4 method, four function evaluations are required. These function evaluations involve calculating the value of the differential equation at certain points within the step using intermediate values.
The RK4 method is known for its accuracy and stability, making it a popular choice for numerical solutions of initial value problems in various fields of mathematics, physics, and engineering.