Suppose

Question

a
represents some number of radians where
0
<
a
<
π
2
, and
cos
(
a
)
=
0.7
and
sin
(
a
)
=
0.72
. Determine the values of the following expressions.

cos
(
−
a
)
=


sin
(
−
a
)
=


Hint: it might help to start by drawing a diagram of two angles: one with a measure of
a
radians, and one with a measure of
−
a
radians.

Answer 1

your bizarre text formatting makes my eyes bleed.