We have,
g(x)=x∫0(|sint|+|cost|) dt
Now,
g(x+nπ2)=x+nπ2∫0(|sint|+|cost|)dt=x∫0(|sint|+|cost|)dt+x+nπ2∫x(|sint|+|cost|)dt
Using the property:
a+nT∫af(x) dx=nT∫0f(x) dx
⇒g(x+nπ2)=g(x)+nπ2∫0(|sint|+|cost|)dt
As (|sint|+|cost|) has a period π2
⇒g(x+nπ2)=g(x)+g(nπ2)⇒g(x+nπ2)=g(x)+nπ2∫0(|sinx|+|cosx|)dx⇒g(x+nπ2)=g(x)+nπ2∫0(sinx+cosx)dx⇒g(x+nπ2)=g(x)+n[sinx−cosx]π20∴g(x+nπ2)=g(x)+2n