Hi members,

in changin from cartesian to polar coordinates they use:

x=r*cos(phi)

y=r*sin(phi)

then using the chain rule delta u/delta r=delta u/delta x.delta x/delta r+delta u/delta y.delta y/delta r

My question:

Delta x/delta r=cos(phi) (here delta means partial derivative)

Is it delta x=delta r*cos(phi).How is it calculated????

Thank you