Quadrants 2 and 4 because in quadrant 2, cosine is negative and sin is positive, while in quadrant 4, cosine is positive and sin is negative
ANSWER
The solution is 
EXPLANATION
We want to solve the simultaneous equations
and
.
We substitute equation (2) in to equation (1), to obtain
This has now become a linear equation in a single variable 
.
We solve for x by grouping like terms.
We divide through by negative 3 to get;
.
Hence, the solution is
Answer:
Step-by-step explanation:
8/15 + 2/5 = 8/15 + 6/15 + 14/15
The sum of any arithmetic sequence is the average of the first and last terms times the number of terms.
Any term in an arithmetic sequence is:
a(n)=a+d(n-1), where a=initial term, d=common difference, n=term number
So the first term is a, and the last term is a+d(n-1) so the sum can be expressed as:
s(n)(a+a+d(n-1))(n/2)
s(n)=(2a+dn-d)(n/2)
s(n)=(2an+dn^2-dn)/2
However we need to know how many terms are in the sequence.
a(n)=a+d(n-1), and we know a=3 and d=2 and a(n)=21 so
21=3+2(n-1)
18=2(n-1)
9=n-1
10=n so there are 10 terms in the sequence.
s(n)=(2an+dn^2-dn)/2, becomes, a=3, d=2, n=10
s(10)=(2*3*10+2*10^2-2*10)/2
s(10)=(60+200-20)/2
s(10)=240/2
s(10)=120
Answer:
It's the top one. No further explanation is needed.
Step-by-step explanation:
We know that a square is made-up of four equivalent sides, and four right angles. So, by process of elimination, you are left with the top one.
Another way of getting the same answer is we know that the only quadrealateral with four equivalent sides is a square, so the top answer is correct.
There you have two, different explainations and ways of getting the same answer, proving that it is correct. Hope that helps!
