We are to verify the identity:
cos(α-B)-cos(α+B) = 2 sinα sinβ
Left hand side = cos(α - B)-cos(α + B)
= cosα cosβ + sinα sinB - (cosα cosB - sinα sinβ)
= cosα cosβ + sinα sinB - cosα cosB + sinα sinβ)
= sinα sinβ + sinα sinβ
= 2 sinα sinβ
= Right Hand side
Using the percentage concept, it is found that 75% of the population of Gorgeous Sunset is on Beautiful Sunrise now.
<h3>What is a percentage?</h3>
The percentage of an amount a over a total amount b is given by a multiplied by 100% and divided by b, that is:

In this problem, we have that:
- We consider that the population of both Beautiful Sunrise and Gorgeous Sunset islands is of x.
- There is a fiesta at Beautiful Sunrise, and a number a of people from Gorgeous Sunset are coming, hence, there will be x + a people at Beautiful Sunrise and x - a people t Gorgeous Sunset.
The percentage of people from Gorgeous Sunset is on Beautiful Sunrise now is:

Now the number of people on Beautiful Sunrise is seven times the number of people on Gorgeous Sunset, hence:

We can find a <u>as a function of x</u> to find the percentage:





Then, the percentage is:




75% of the population of Gorgeous Sunset is on Beautiful Sunrise now.
You can learn more about the percentage concept at brainly.com/question/10491646
Step-by-step explanation:
2x²+3x-2=0
(2x-1)(x+2)
x+2=0
x=-2 (no, because x must be >0)
2x-1=0
2x=1
x=½ (yes, because x>0)
Answer:
10
Step-by-step explanation: