Answer:
true
Step-by-step explanation:
1/2 (sin(x+y)+sin(x-y))
= 1/2 (sin x cos Y + cos x sin y + sin x cos y - cos x sin y)
= 1/2 * 2 sin x cos y
= sin x cos y
The expression is true.
1.) v=(l)(w)(h)
V=(9)(9)(9)
V=(81)(9)
V=729in^3
2.) (I forget if this is the real equation to this but this would give you the same answer)
V=(l)(w)(h)
————
2
V=(8)(6)(12)
————-
2
V=576/2
V=288cm^3
-10 and -2
Because -10-2= -12 and -10 x -2 = 20
Hope this helps :)
Let's make things easier by simplifying things.
y = 8 and x = 3 is more likely to be understood as a ratio. So for the rest of the answer, their relationship would be represented as y:x
Thus: y:x = 8:3
The problem would be finding y when x = 45
Let us proceed on using the previous equation and substitute x with 45 which would look like this:
y:45 = 8:3
Ratios can also be expressed as fractions which would make things more understandable and easy to solve. So the new form of our equation would be like this:
y/45 = 8/3
Then we proceed with a cross multiplication where the equation becomes like as what is shown below:
3y = 45 * 8
From there, you can solve it by multiplying 45 and 8 then dividing the product with 3 to get y
3y = 360
y = 120
Another way of looking at the problem, especially problems like these, is to take the whole question or statement as an equation. it would probably look like this:
y = 8 when x = 3 : y = ? when x = 45
This would make you understand what approach you can use to solve the given problem.
y-axis = altitude in feet
x-axis = minutes
slope = y/x = feet/minute
According to above data, we know that 1800 feet is y-intercept and slope is -300 feet per minute (why slope is negative? because its approaching ground at a constant speed)
a. slope = -300
y-intercept = 1800
b. y = -300 x + 1800
c. Here we are given x = 2 minutes
y = -300(2) + 1800
y = -600 + 1800
y = 1200
The balloon will be 1200 feet high above the ground in 2 minutes.
d. Here we are given 300 feet which is y, and find x minutes.
y = -300 x + 1800
300 = -300x + 1800
300 - 1800 = - 300x
-1500 = -300x
1500 = 300 x
x = 1500 / 300
x = 5
The balloon will reach 300 feet above the ground in 5 minutes.
e. It asking when the balloon will reach the ground, if the balloon reaches the ground than the height will be 0, therefore x-intercept (y=0).
y = -300 x + 1800
0 = -300 x + 1800
-1800 = -300x
1800 / 300 = x
x = 6
The balloon will reach the ground in 6 minutes.
<em>//Hope this helps</em>
