As a tangent is a straight line it is described by an equation in the form \(y - b = m(x - a)\). You need both a point and the gradient to find its equation. You are usually given the point - it's ...

From lens focal lengths and fill-flash to portraits, macro or stunning landscapes there are techniques for everyone. Learn how to use metering, considering composition and shoot everything from ...

An example of this can be seen below. Once the tangent is found you can use it to find the gradient of the graph by using the following formula: \(\text{Gradient to the curve =}~\frac {y_2-y_1} ...