Definition

a implicit method

𝑦𝑘+1=𝑦𝑘+𝑓(𝑡𝑘,𝑦𝑘)+𝑓(𝑡𝑘+1,𝑦𝑘+1)2

Stability

It’s sable if

|1+𝜆21𝜆2|1

for every 𝜆 as Eigenvalue