Perpendicular lines will always cross at right angles. To determine if two lines are perpendicular, we need to multiply their gradients together. If the lines are perpendicular to each other ...

Find the equation of a straight line that is perpendicular to \(y = 2x + 1\). The gradient of \(y = 2x + 1\) is 2. The reciprocal of 2 is \(\frac{1}{2}\), so the negative reciprocal of 2 is ...