Answer:
See Below.
Step-by-step explanation:
We want to verify the identity:

Note that the left-hand side is a perfect square trinomial pattern. Namely:

If we let <em>a</em> = csc(x) and <em>b</em> = cot(x), we can factor it as such:

Let csc(x) = 1 / sin(x) and cot(x) = cos(x) / sin(x):

Combine fractions:

Square (but do not simplify yet):

Now, we can make a substitution. Let <em>u</em> = <em>x</em> / 2. So, <em>x</em> = 2<em>u</em>. Substitute:

Recall that cos(2u) = 1 - sin²(u). Hence:

Simplify:

Recall that sin(2u) = 2sin(u)cos(u). Hence:

Square:

Cancel:

Since sin(u) / cos(u) = tan(u):

We can substitute <em>u</em> back for <em>x</em> / 2:

Hence proven.
Answer:
C: -3/7
Step-by-step explanation:
Put an extended line over each direct point you see and then count the graph it takes to reach the nearest point.
Here is a picture to better explain it!
Answer:
You should go with the 1st, because it's cheaper.
Step-by-step explanation:
1st plan:
30$ which include 75 mins of free calls and 100 free text messages
25 more mins * 10¢ /min(0.1$/min) = 2.5$
You will pay 32.5$
2nd plan:
(calls)100*0.3$=30$
(text messages)100 * 0.1$=10$
30+10 = 40$