Answer:
Step-by-step explanation:
If our interval is between 0 and 90 degrees, that means that our angles are first quadrant angles. Since the formulas for the half angles of sin and cos consider both the positive and negative roots, knowing that we are in QI leaves us using only the principle, or positive, root.
Also, if we know that the sin of angle is 3/4, we can set up a right triangle in QI and find the missing side of that triangle using Pythagorean's Theorem. Sin of an angle is the ratio opposite side/hypotenuse. That means that, according to Pythagorean's Theorem,
and
and

Now for the forula for the sin of a half-angle:

Referring to the right triangle we created and found the missing side for, we see that the cosine of that same triangle is 
Filling in the formula then:

Get a common denominator on the upper fraction:

Bring up the 2 as 1/2 to multiply and get:

When you do the exact same thing to find the cos of the half angle, you are using a + sign instead of a - sign under the radical. That gives you as your exact value:

Answer:
Step-by-step explanation:
x = 0.8 + 0.2y
Answer:
3,000
Step-by-step explanation:
Create 2 expressions to represent the cost and the revenue, where x is the number of newspapers:
2x + 15,000 will represent the cost
5x + 6,000 will represent the revenue
Set the expressions equal to each other and solve for x:
2x + 15,000 = 5x + 6,000
15,000 = 3x + 6,000
9,000 = 3x
3,000 = x
So, 3,000 newspaper copies have to be sold to break even
Answer:10:11 am
Step-by-step explanation:
Answer:
<u>4(1 – x) + 2 x = -3( x + 1)</u>
first do 4 time 1= 4
then do 4 times x =4x
now the equation should look like this
4-4x+2x=-3(x+1)
then do the other side of the equation
-3(x+1)
=-3x-3
Now collect the like terms:
-4x-2x
now the equation should look like this
4-2x=-3x-3
now add 3x add on both sides
4-2x+3x=-3
put the 4 on the other side
-2x+3x=-3-4
now again collect the like terms (-2x+3x=1 which is just x and -3-4 =-7)
x=-7
answer
x=-7