In this part you do not have to sketch the graph and you may even be given the sketch of the graph to start with. For a quadratic equation of the form \(y = k{(x - a)^2} + b\), the following diagram ...

Given any expression of the form \(a\cos x + b\sin x\) it is better to rewrite it into one of the forms \(k\cos (x \pm \alpha )\) or \(k\sin (x \pm \alpha )\) before answering the question. From this ...