Question

Please help me solve the following problem. I am asked to sketch the circle r(t)=cost(i)+sint(j) and draw the vector r'(pi/4) with its correct length. I already drew the circle but how do I obtain a value for the vector?

Answer 1

r'(t)=<-sint,cost>

Answer 2

r'(pi/4)=<-sqrt(2)/2,sqrt(2)/2>

Answer 3

Is that right so far? How do I draw that vector? How do I determine its origin?

Answer 4

t=pi/4 is the origin of the vector, yes?