250 likes | 437 Views
1.2 Differential Calculus. 1.2.1 The Gradient. points in the direction of maximum increase of T. It is perpendicular to the surface T=const. gives the slope (rate of increase) along this direction. T(x,y)=const. θ. y. x. gradient:. Example: Multiplication by a scalar-the gradient.
E N D
points in the direction of maximum increase of T. It is perpendicular to the surface T=const. gives the slope (rate of increase) along this direction. T(x,y)=const. θ y x gradient:
Example: Multiplication by a scalar-the gradient. The order of the factors does matter! 1.2.3 The “del” Operator The del is similar to a vector, but it is an operator. It acts on (takes the partial derivatives of) everything to its right.
1.2.4 The Divergence divergence of a vector field
large divergence no divergence
F(x,y) = (2*x,-y)-(6,-1). F(x,y) = (2*x,-y).
1.2.5 The Curl Curl of the a vector field Keep track of the order in evaluating the determinant!
G(x,y) - G(x0,y0) (-y-3,x-3) (-y+3,x+3)
Turbulent motion of air around a vibrating cylinder in a wind tunnel.
1.2.6 Product Rules • Apply del to all factors. • Keep track of the type of multiplication (dot vs. cross, how connected). • Arrange in standard form (gradient, curl, divergence). • Most important products are listed in the book.