We'll use the following properties of sine and cosine to prove this:



Then it's just a matter of filling it in...
sin20sin40 * sin60sin80 = 1/2(cos20 - cos60) * 1/2 (cos20 - cos140) =
1/8( cos40 + 1 - cos160 - cos120 - cos40 - cos80 + cos80 + cos200) =
1/8(1 - cos160 - cos120 + cos200) =
1/8(1 - cos160 - cos120 + cos160) =
1/8(1 - cos120 ) = 1/8( 1 + 1/2 ) = 3/16
Complete Question:
If the point (2, 5) is a solution to the system of equations shown below, then determine the missing values of b and m. Show how you arrive at your answer.
1. y = 3x + b
2. y = mx + 9
Answer:
1. Intercept, b = -1
2. Slope, m = -2
Step-by-step explanation:
Given the following data;
Points on the line (x, y) = (2, 5)
To find the missing values;
Mathematically, the equation of a straight line is given by the formula;
y = mx + b
Where;
- m is the slope.
- x and y are the points
- b is the intercept.
1. y = 3x + b
Substituting the value of x and y, we have;
5 = 3(2) + b
5 = 6 + b
b = 5 - 6
<em>Intercept, b = -1</em>
2. y = mx + 9
Substituting the value of x and y, we have;
5 = m(2) + 9
5 = 2m + 9
2m = 5 - 9
2m = -4
m = -4/2
<em>Slope, m = -2</em>
Answer:
D. 116
Step-by-step explanation:

V = (1/3)π(4)²(6.9)
V = 36.8π
V ≈ 115.55
<em>Note: You will NEVER use slant height to calculate the area, only to calculate the normal height if unknown. In this problem, we did not use it at all so try not to get confused!</em>
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<h2>BRAINLIEST please if this helped!</h2>
This kinda sounds like system of equations to me. Let's use some variables. 'x' would be the fee for the regular selections. 'y' would be the fee for the discounted selections. Let's start making our equations :O. Here's Pat's order: 2x+4y=119.80. Here's Carlos' order: 3x+5y=160.75. Now, there are different ways of solving these variables such as using substitution, but I will use linear combinations method/elimination method to solve this. I will try to make one variable value the opposite of the other equation's variable. I can get 6x+10y=321.50 and -6x-12y=-359.4. I can eliminate the x now and only have variable y. -2y=-37.9. Dividing both sides gets me y=18.95. I can substitute the y value for y in any equation. so 2x+4(18.95)=119.80. 2x+75.8=119.80. 2x=44. 2x/2=44/2. x=22. Therefore, the fee for regular selections is 22 while the fee for discounted selections is 18.95. Hope you enjoyed this session of learning :3