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Brums [2.3K]
3 years ago
12

Sin5A/SinA-cos5A/cosA=4cos2A​

Mathematics
1 answer:
irina1246 [14]3 years ago
5 0

Answer:

See Explanation

Step-by-step explanation:

\frac{ \sin5A}{\sin A}  -  \frac{ \cos5A}{\cos A}  = 4\cos2A \\  \\ LHS = \frac{ \sin5A}{\sin A}  -  \frac{ \cos5A}{\cos A}   \\  \\  =  \frac{ \sin5A \:\cos A -  \cos5A \:  \sin A}{\sin A \:\cos A }  \\  \\  =  \frac{ \sin(5A -A )}{\sin A \:\cos A}  \\  \\ =  \frac{ \sin 4A}{\sin A \:\cos A}  \\  \\ =  \frac{ 2\sin 2A \: \cos 2A}{\sin A \:\cos A}  \\  \\ =  \frac{ 2 \times 2\sin A \: \cos A \: \cos 2A}{\sin A \:\cos A}  \\  \\ =  \frac{ 4\sin A \: \cos A \: \cos 2A}{\sin A \:\cos A}  \\  \\ =4\cos 2A \\  \\  = RHS \\  \\ thus \\  \\  \frac{ \sin5A}{\sin A}  -  \frac{ \cos5A}{\cos A}  = 4\cos2A \\  \\ hence \: proved

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The cross section of a parabolic reflector has a vertical axis of symmetry with its vertex at (0,0) . The focus of the reflector
Paha777 [63]

Answer:

The depth of the reflector is 0.84 feet

Step-by-step explanation:

<em>(See the figure below)</em>

The equation of a parabola centered at the origin with an axis of symmetry on y-axis is:

x^{2}=4py (1)

With p the distance from the origin to the focus using p=6, the equation (1) of the parabola becomes:

x^{2}=4(6)y=24y (2)

Note that the point B is on the parabola, so this point should satisfy the parabola equation (2) that allow us to use the value x=4.5 to find the y value associated to it, that it is the depth (h) of the reflector:

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y=\frac{(4.5)^{2}}{24}\approx0.84\,ft

4 0
3 years ago
INT1 4.1.1 Line of Best Fit (classwork)
Lorico [155]

Answer:

a. 2401.06

b. 37.54%

c. 56.3%

Step-by-step explanation:

hopefully this is right

*note: I think you forgot to convert 4-2 back into yards.

a. Robbie's field of view to the North end includes parts not on the football field. so to find the area of the football field he can see, we need to find:

total area of what Robbie sees - area of non football field Robbie sees

what you shaded represents the total of what Robbie sees. it's a triangle. area of a triangle is 1/2(b)(h) where h is distance away and b is width of view.

total area = 1/2(170)(30.92) = 2628.56 yd

area of non football field (pipe to South end)

= 1/2(50)(9.1) = 227.5

so 2628.56 - 227.5 = 2401.06

b. area found in part a / total area of football field

2401.06 / (120*53.3) = .3754

.3754 * 100 = 37.54%

c. the chance of Robbie seeing the touchdown depends on how much of the (North) endzone he can see.

area of north endzone is

10 * 53.3 = 533.

area Robbie sees in endzone is

2628.56 - 2328.48 = 300.08

(found by total area Robbie sees - area of non endzone Robbie sees)

300.08 / 533 = 0.563

= 56.3%

7 0
3 years ago
Is the LCM ( least common multiple) of two numbers ( always,sometimes,never) the product of the two numbers?
Scorpion4ik [409]
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3 years ago
Karens batting average was 0.444. She was at bat 45 times. How many hitd did she get?
Igoryamba
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3 years ago
The length of one leg of an isosceles right triangle is 7 units. What is the length of the hypotenuse?
Westkost [7]
Given that the hypotenuse of the isosceles right triangle
=
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,
⇒
the length of each leg
=
14
√
2
=
7
√
2
Check :
(
7
√
2
)
2
+
(
7
√
2
)
2
=
196
=
14
2
(OK)
5 0
3 years ago
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