Hai PF, I had a doubt in the sector of partial differential equation using one dimensional wave equation. Actually the problems is below mentioned A string is stretched and fastened at two points x=0 and x=2l apart. motion is strated by displacing the string in the form y=k(2lx-[x][/2]) from which it is released at time t=0.find the displacement of the string at any time 't'. I had attached a diagram. In that they had mentioned x-axis as string length & y-axis as displacement. Is this possible for a one dimensional equation? For one dimensional equation there may exist one spatial dimension & space(i.e time). But in this problem they had given two co-ordinate axis & they had continue the sum with one dimensonal equation. How this is possible? Can anyone explain?