First solve the quadratic as you would an equation, so you will get two real zeroes p and q so that (x-p)(x-q)=0 is another way of expressing the quadratic. All quadratics can be represented graphically by a parabola, which could be inverted. When the x² coefficient is negative it’s inverted. If the coefficient of x² isn’t 1 or -1 divide the whole quadratic by the coefficient so that it takes the form x²+ax+b, where a and b are real fractions. The curve between the zeroes will be totally below the x axis for an upright parabola, and totally above for an inverted parabola. This fact is used for inequalities. An inequality will be <, ≤, > or ≥. This makes it easy to solve the inequality. If the position of the curve between the zeroes is below the axis then outside this interval it will be above, and vice versa. So we’ve defined three zones. x
q, and p
Answer: Either 25.0 or 25 depending on how your teacher wants you to format the answer
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Explanation:
To start off, it probably helps to translate what the question wants.
It states "For the pilot of airplane B, calculate the angle between the lines of sight to the airplane at C and Jenny's airplane [at point A]".
This fairly long, and possibly complex, sentence boils down to "find angle B"
To find angle B, we need to find the length of side 'a' first
Let,
a = x
b = 4.2
c = 5.7
Note how the lowercase letters (a,b,c) are opposite their uppercase counterparts (A,B,C). This is often the conventional way to label triangles. The lowercase letters are usually for the side lengths while the upper case is for the angles.
We have angle A = 120 degrees
Plug these values into the law of cosines formula below. Then solve for x
a^2 = b^2 + c^2 - 2*b*c*cos(A)
x^2 = 4.2^2 + 5.7^2 - 2*4.2*5.7*cos(120)
x^2 = 17.64 + 32.49 - 47.88*cos(120)
x^2 = 17.64 + 32.49 - 47.88*(-0.5)
x^2 = 17.64 + 32.49 + 23.94
x^2 = 74.07
x = sqrt(74.07)
x = 8.60639297266863
x = 8.6064
So side 'a' is roughly 8.6064 kilometers when we round to four decimal places
Now we'll use this to find angle B
Use the law of cosines again, but this time, the formula is slightly altered so that angle B is the focus instead of angle A
Plug in the side lengths (a,b,c). Solve for angle B
b^2 = a^2 + c^2 - 2*a*c*cos(B)
(4.2)^2 = (8.6064)^2 + (5.7)^2 - 2*(8.6064)*(5.7)*cos(B)
17.64 = 74.07012096 + 32.49 - 98.11296*cos(B)
17.64 = 106.56012096 - 98.11296*cos(B)
17.64 - 106.56012096 = 106.56012096 - 98.11296*cos(B)-106.56012096
-88.92012096 = -98.11296*cos(B)
(-88.92012096)/(-98.11296) = (-98.11296*cos(B))/(-98.11296)
0.906303519535034 = cos(B)
cos(B) = 0.906303519535034
arccos(cos(B)) = arccos(0.906303519535034)
B = 25.0005785532867
It's a bit messier this time around, but we get the approximate angle
B = 25.0005785532867
which rounds to
B = 25.0 degrees
when we round to the nearest tenth. We can write "25.0" as simply "25"
Answer:
8%
Step-by-step explanation:
1) create equation
y = (4)2.5 + 125
2) simplify
y = 10 + 125
y = 135
3) find difference
x = 135-125/125
x = 0.08
x = 8%
Correct sets are:
- Multiples of 4 are even numbers. -------------- Set C
- The set of all vowels.------------------------------- A ∩ B
- The intersection of even numbers and odd numbers ---- ∅ ( empty set )
- The set of numbers and all vowels-------------- Set A or set B, or A ∪ B.
<span>width = x
</span><span>length = x+5
2x + 2(x+5) = 46
2x + 2x + 10 = 46
4x = 46 - 10
4x = 36
x = 36/4 </span><span>
x = 9 in </span> ← width
length = x+5 = 9 + 5 = 14 in
<span>
Area = 9 * 14 = 126 in</span>²<span>
</span>