Answer:
The correct option is C
Step-by-step explanation:
The organizers of a fair projected a 25 percent increase in attendance this year over that of last year
Let x = the attendance for last year
The projected attendance for this year would be last year's attendance + 25% of last year's attendance. This means
Projected attendance for this year
= x + 25/100 × x
= x + 0.25x = 1.25x
But attendance for this year actually decreased by 20 percent.
This means the actual attendance for this year would be
attendance for last year - 20% of attendance for last year. This means
Actual attendance for this year is
x - 20/100 × x
= x - 0.2x = 0.8x
percentage of the projected attendance that was the actual attendance would be
0.8x / 1.25x × 100 = 0.64 × 100
= 64%
The correct option is C
Answer:
5y
Step-by-step explanation:
Answer:
φ ≈ 1.19029 radians (≈ 68.2°)
Step-by-step explanation:
There are simple formulas for A and φ in this conversion, but it can be instructive to see how they are derived.
We want to compare ...
y(t) = Asin(ωt +φ)
to
y(t) = Psin(ωt) +Qcos(ωt)
Using trig identities to expand the first equation, we have ...
y(t) = Asin(ωt)cos(φ) +Acos(ωt)sin(φ)
Matching coefficients with the second equation, we have ...
P = Acos(φ)
Q = Asin(φ)
The ratio of these eliminates A and gives a relation for φ:
Q/P = sin(φ)/cos(φ)
Q/P = tan(φ)
φ = arctan(Q/P) . . . . taking quadrant into account
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We can also use our equations for P and Q to find A:
P² +Q² = (Acos(φ))² +(Asin(φ))² = A²(cos(φ)² +sin(φ)²) = A²
A = √(P² +Q²)
_____
Here, we want φ.
φ = arctan(Q/P) = arctan(5/2)
φ ≈ 1.19029 . . . radians
These are right triangles that will use either sin, cos, or tan, depending upon what you have to work with in regards to the reference angle. The first one has a reference angle of 51 with y being the side opposite it and 12 being the hypotenuse. The sin identity uses the side opposite over the hypotenuse as its formula:

and 12 sin(51) = y and y = 9.325
The second one has the reference angle as the unknown. You could use any of the identities here because you have all the sides of the triangle, but I will use sin again:

and

and

The next one has a referece angle of 13 with 24 being the side adjacent to it and the unknown being the side across from it. You will use the tangent identity here:

and 24 tan(13) = x so x = 5.540
The last one has a reference angle of 20 with the hypotenuse as the unknown x, and the side across from it as 10. Use the sin identity again:

and

and

with x = 29.238
Everything is in regards to the reference angle; you HAVE to be able to identify the reference angle and then how the given sides are related to it.
The answer is: y= –1/3x–5