Find the derivative with respect to x, of 5cos(x)+ 4sin(x)

f(x) = 5cos(x) + 4sin(x)to find f^,(x) this is just another notation for the derivative.To differentiate trigonometry I always use this one simple trick which I will show on the white board better sin cos -sin -cosWhen you differentiate sin or cos you move down this list and it loops round. This helps you keep track of the sign.following this notation the final answer will bef^,(x) = -5sin(x) + 4cos(x).