Answer :
Step-by-step explanation:
7
√
15
32
=
0.85
Explanation:
sin 2t = 2sin t.cos t
Knowing
cos
t
=
−
7
8
, find sin t.
Trig identity:
sin
2
a
=
1
−
cos
2
a
-->
sin
2
t
=
1
−
cos
2
t
=
1
−
49
64
=
15
64
sin t = +- sqrt15/8.
Arc t is in Quadrant III, then, sin t is negative.
sin
2
t
=
2
(
−
7
8
)
(
−
√
15
8
)
=
7
√
15
32
=
0.85
hope this helps :)