How do you take the derivative of arctan(y/x) with respect to x??
Why is this listed under "differential equations"?
Are we to assume that y is not a function of x? Then use the chain rule, of course. The derivative of arctan(u), with respect to u, is . By the chain rule, with u= y/x, the derivative of arctan(y/x), with respect to x, is . Of course, you differentiate , with respect to x, by treating y as a constant.