We can estimate the average value of a region of level curves by using the formula (1/A(R)) int int_R f(x,y) Delta(A), where A(R) is the area of the rectangle defined by R=[x1,x2]x[y1,y2], and where the double integral gives the volume under the surface f(x,y) over the region R.
Read MoreJust as we did with single variable functions, we can use the second derivative test with multivariable functions to classify any critical points that the function might have. To use the second derivative test, we’ll need to take partial derivatives of the function with respect to each variable. Once we have the partial derivatives, we’ll set them equal to 0 and use these as a system of simultaneous equations to solve for the coordinates of all possible critical points.
Read MoreTo find the linear approximation equation, find the slope of the function in each direction (using partial derivatives), find (a,b) and f(a,b). Then plug all these pieces into the linear approximation formula to get the linear approximation equation.
Read MoreGiven a region defined in uvw-space, we can use a Jacobian transformation to redefine it in xyz-space, or vice versa. We’ll use a 3x3 determinant formula to calculate the Jacobian.
Read MoreThe gradient vector formula gives a vector-valued function that describes the function’s gradient everywhere. If we want to find the gradient at a particular point, we just evaluate the gradient function at that point.
Read MoreBefore we can use the formula for the differential, we need to find the partial derivatives of the function with respect to each variable. Then the differential for a multivariable function is given by three separate formulas.
Read MoreFinding derivatives of a multivariable function means we’re going to take the derivative with respect to one variable at a time. For example, we’ll take the derivative with respect to x while we treat y as a constant, then we’ll take another derivative of the original function, this one with respect to y while we treat x as a constant.
Read MoreWhenever you're dealing with a multivariable function, the graph of that function will be a three-dimensional figure in space.
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