Periodic Boundary Value Problem for Second Order Functional Differential Equations

Consider the delay – differential equation (1.1) − u ″ ( t ) = f ( t , u ( t ) , u t ) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003067498/6ba0c26b-f086-40cc-86ed-1693dc596221/content/eq3042.tif"/>