Cosine Curve

The applet below has 4 different transformations of the curve, y=cos x. Move the sliders for a,b,c, and d, and see how the graph changes. Note: x is in radians. You can also show the sine curve, by pushing the check box. Play around until you understand the idea, and then answer the questions below.
Question 1: Describe the transformation, that moves y=cos x to y=sin x. Consider the general cosine curve, y=a cos (b(x-c))+d. Question 2: Write the amplitude, principal axis, period, minimum, and maximum of the general cosine curve. Question 3: How does your answers to question 2 match y=sin x?