Hi, I have this diff. question which i keep getting wrong:

Find dy/dx of:

v=1/(1+e^-x)

This is my working:

v=1/1 + 1/(e^-x)=1+1/(e^x)=1+e^x

therefore dy/dx would equal :

e^x

could someone please show me where i'm going wrong...:confused:

Thank you