Posted by Sarah on Tuesday, September 23, 2008 at 8:40pm.
The displacement (in centimeters) of a particle moving back and forth along a straight line is given by the equation of motion s= 2 sin pi t + 3 cos pi t, where t is measured in seconds.
(a) Find the average velocity during each time period:
(i)[1,2]
(ii) [1,1.1]
(iii) [1, 1.01]
(iv) [1, 1.001]
(b) Estimate the instantaneous velocity of the particle when t=1.
Can someone please help me with this question, the trig functions have me confused. Please and thanks again.

trig  bobpursley, Tuesday, September 23, 2008 at 8:43pm
PUt in the times given, first the final time,then calculate position, then put in the initial time, and calculate position.
avg velocity=(finalpositioninitialposition)/timeduration 
trig  Sarah, Tuesday, September 23, 2008 at 9:00pm
but how do we treat the cos and sin...just input them like that into the calculator or use radians?

trig  Sarah, Tuesday, September 23, 2008 at 9:23pm
and also for (b) is the answer 2pi

trig  Sarah, Tuesday, September 23, 2008 at 10:03pm
i got 3 for all part a can anyone verify that answer please