Find u(3/4,2) when l=c=1, f(x) = x(1-x), [itex] g(x) = x^2 (1-x) [/itex] all i need to do is find the value using d'Alembert's solution of the one dimensional wave. now it is easy for me to extend f(x) for f(x) [tex](-1,0)\Rightarrow \quad x(1+x)[/tex] [tex](0,1)\Rightarrow \quad x(1-x)[/tex] [tex](1,2)\Rightarrow \quad -(x-1)+(x-1)^2[/tex] [tex](2,3)\Rightarrow \quad (x-2)-(x-2)^2 [/tex] but for g(x) for extnesion into the (1,2) interval i get [tex] (x-1)^2 (x-2) [/tex] but i was told that the answer is [tex] -(2-x)^2 (x-1)][/tex] which is switched from my answer. WHy is it the oppsoite? WHo is correct? WHat i did is isketched this little piece of function for the (0,1) interval and then reflected it on the X axis. I then moved it right by one place to theh right by -1 factor. Also is it ok the solve the one dimensional wave equation using separation of variables rather than using d'Alembert's solution? Please advise! Thank you for your help!