A spring is moving up and down according to the function s(t) = -4cos(t).
Part a) Find the first derivative and calculate the velocity of the spring at t = 3pi/4 ?
Part b) Is the spring moving upward or downward at this point? Justify your answer.

Question

A spring is moving up and down according to the function s(t) = -4cos(t). 
Part a) Find the first derivative and calculate the velocity of the spring at t = 3pi/4 ? 
Part b) Is the spring moving upward or downward at this point? Justify your answer.

anonymous · Answer

the only difference between f(x) and f'(x) is that the trig function changes to its d/dx

anonymous · Answer

then plug P into y' and graph

lena772 · Answer

Thanks. It'd be moving upward if positive right?

ganeshie8 · Answer

yes,

S'(3pi/4) = positive means, S is increasing at t = 3pi/4

ganeshie8 · Answer

since s(t) is modeling height of spring, 
"increasing" refers to "climbing up"