Answer:
She rewrote the problem without parentheses: x3+ 2x2 - x + x3 – 2x2 +6
Step-by-step explanation:
It looks like she didn't fully distribute the -
(x3 + 2x2 - x)-(-x3 + 2x2 + 6) :Original
x3+ 2x2 - x + x3 – 2x2 +6 :Changed
~
(x3 + 2x2 - x)-(-x3 + 2x2 + 6)
x3 + 2x2 - x + x3 - 2x2 - 6
x3 + x3 + 2x2 - 2x2 -x - 6
2x3-x-6
I hope this helps ^-^
Answer:
You can prove this statement as follows:
Step-by-step explanation:
An odd integer is a number of the form 
where 
. Consider the following cases.
Case 1. If 
is even we have: 
.
If we denote by 
we have that 
.
Case 2. if is odd we have: 
.
If we denote by 
we have that
This result says that the remainder when we divide the square of any odd integer by 8 is 1.
Find <span>tan<span>(<span><span>5π</span>12</span>)</span></span> and sin ((5pi)/12)
Answer: <span>±<span>(2±<span>√3</span>)</span>and±<span><span>√<span>2+<span>√3</span></span></span>2</span></span>
Explanation:
Call tan ((5pi/12) = t.
Use trig identity: <span><span>tan2</span>a=<span><span>2<span>tana</span></span><span>1−<span><span>tan2</span>a</span></span></span></span>
<span><span>tan<span>(<span><span>10π</span>12</span>)</span></span>=<span>tan<span>(<span><span>5π</span>6</span>)</span></span>=−<span>1<span>√3</span></span>=<span><span>2t</span><span>1−<span>t2</span></span></span></span>
<span><span>t2</span>−2<span>√3</span>t−1=0</span>
<span>D=<span>d2</span>=<span>b2</span>−4ac=12+4=16</span>--> <span>d=±4</span>
<span>t=<span>tan<span>(<span><span>5π</span>12</span>)</span></span>=<span><span>2<span>√3</span></span>2</span>±<span>42</span>=2±<span>√3</span></span>
Call <span><span>sin<span>(<span><span>5π</span>12</span>)</span></span>=<span>siny</span></span>
Use trig identity: <span><span>cos2</span>a=1−2<span><span>sin2</span>a</span></span>
<span><span>cos<span>(<span><span>10π</span>12</span>)</span></span>=<span>cos<span>(<span><span>5π</span>6</span>)</span></span>=<span><span>−<span>√3</span></span>2</span>=1−2<span><span>sin2</span>y</span></span>
<span><span><span>sin2</span>y</span>=<span><span>2+<span>√3</span></span>4</span></span>
<span><span>siny</span>=<span>sin<span>(<span><span>5π</span>12</span>)</span></span>=±<span><span><span>√<span>2+<span>√3</span></span></span>2</span></span></span>
