The function is
.
Where
is angular displacement in radians,
is time in seconds.
Find the maximum angular displacement.
\
The cosine function ranges between
to
.
.
is maximum when
is maximum.
The maximum value of
is
.
The maximum angular displacement is
.
Find the rate of change of
when
seconds.

Apply derivative on each side with respect to
.

Apply formula:
.


Substitute
in above function.


.
Rate of change of
when
is
rad/sec.
The maximum angular displacement is
rad.
Rate of change of
when
is
rad/sec.