for 𝑦″+𝑝(𝑡)𝑦′+𝑞(𝑡)𝑦=0 𝑊(𝑡)=𝑊(𝑦1,…,𝑦𝑛)(𝑡)=𝑐𝑒−∫𝑝(𝑡)𝑑𝑡 where 𝑊 is Wronskian determinant and 𝑐 is a constant by 𝑊 at convenient point.