Answer:
D
Step-by-step explanation:
We are given that:

And we want to find the value of tan(2<em>x</em>).
Note that since <em>x</em> is between π/2 and π, it is in QII.
In QII, cosine and tangent are negative and only sine is positive.
We can rewrite our expression as:

Using double angle identities:

Since cosine relates the ratio of the adjacent side to the hypotenuse and we are given that cos(<em>x</em>) = -1/3, this means that our adjacent side is one and our hypotenuse is three (we can ignore the negative). Using this information, find the opposite side:

So, our adjacent side is 1, our opposite side is 2√2, and our hypotenuse is 3.
From the above information, substitute in appropriate values. And since <em>x</em> is in QII, cosine and tangent will be negative while sine will be positive. Hence:
<h2>

</h2>
Simplify:

Evaluate:

The final answer is positive, so we can eliminate A and B.
We can simplify D to:

So, our answer is D.
Answer:
In ∆ABD and ∆ACD
<BAD =<CAD ( each are half of <A )
<D=<D ( each equal to 90°)
AD = AD ( common)
So ∆ ABD is congruent to ∆ ACD.
Then AB =AC (by C.P.C.T)
Hence,∆ABC is an iso - sceles triangle.
Answer:
Which number lies halfway between:
a) 16 and 38 = 28
b) 259 and 361 =310
1004 and 2012?
=1058
Answer:
(a) 
(b) Domain:
<em>(See attachment for graph)</em>
(c) 
Step-by-step explanation:
Given



Solving (a): A function; l in terms of w
All we need to do is make l the subject in 
Divide through by 2

Subtract w from both sides


Reorder

Solving (b): The graph
In (a), we have:

Since l and w are the dimensions of the fence, they can't be less than 1
So, the domain of the function can be 
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To check this
When 



When 


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<em>See attachment for graph</em>
<em></em>
Solving (c): Write l as a function 
In (a), we have:

Writing l as a function, we have:

Substitute
for l in 
becomes

Answer:
x intercept is (-15,0)
Step-by-step explanation: