Cos
θ
=
√
5
3
or it could be cos
θ
=
√
5
−
3
Explanation:
Since sin
θ
is negative, it can be in the third or fourth quadrant
Drawing your right-angled triangle, place your
θ
in one of three corners. Your longest side will be 3 and the side opposite the
θ
will be -2. Finally, using Pythagoras theorem, your last side should be
√
5
Now, if your triangle was in the third quadrant, you would have
cos
θ
=
√
5
−
3
since cosine is negative in the third quadrant
But if your triangle was in the fourth quadrant, you would have
cos
θ
=
√
5
3
since cosine is positive in the fourth quadrant
The sum if the geometric sequence given by:
an=-2(3)^(n-1)
will be:
when:
n=1
an=-2
when n=2
a2=-6
when n=3
a3=-18
when n=4
a4=-54
when n=5
a5=-162
when n=6
a6=-486
when n=7
a7=-1458
when n=8
a8=-4374
thus the summation of the term will be:
Sn=(-4374+-1458+-486+-162+-54+-18+-6+-2)
Sn=-6560
the answer is -6560
Answer: True
Step-by-step explanation:
Prism volume = lwh
Pyramid Volume = lwh/3
Answer:
D
Step-by-step explanation:
