If x1 is some value of x, u1is the corresponding value of u and y1 the corresponding value of y, then dy/dx at x = x1 is the product of dy/du at u1 and du/dx at x1.
This does not make sence....
IF: y = (x+2)^2
y=u^2 u = x+2
dy/du = 2u
du/dx = 1
I want to find the tangent at x = 2
The above statment says dy/dx = dy/du at point u1 time du/dx at point x1
dy/du @ x = 2 is 4
du/dx @ u =2 is 1
4*1 is 4 which is not the correct answer.....