I have tried to solve this question about the function f(x) = cos x + sin x
But it was a bit difficult for me.
The question is:
Consider the function f(x) = cos x + sin x
(i) Show that f(– p/4) = 0.
(ii) Find in terms of p, the smallest positive value of x which satisfies f(x) = 0.
b) The diagram shows the graph of y = ex (cos x + sin x), – 2 £ x £ 3. The graph has a maximum turning point at C(a, b) and a point of inflexion at D.
(I have attached the diagram)
(i) find dy/dx
(ii) Find the exact value of a and of b.
(iii) Show that at D, y = sqrt2 e^ p/4
Thank you very much for your help!