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3 years ago

Find X. Round to the nearest tenth. Law of Cosines : c2 = 22 + b2 - 2ab cos C

Mathematics

1 answer:

fiasKO [112]3 years ago

7 0

Answer:

70.5°

Step-by-step explanation:

22² = (20)²+(18)² - 2(20)(18) cos X

484 = 400 + 324 - 720 cos X

-240 = -720 cosx

1/3 = cos X

$cos^{-1}(\frac{1}{3})$ = X

X = 70.52877937

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sin alpha = 7/25, alpha lies in quadrant ii, and cos beta = 2/5, beta lies in quadrant i. find cos(alpha-beta).

Ilia_Sergeevich [38]

Answer:

Therefore $\cos(\alpha-\beta)=\frac{48+7\sqrt{25}}{125}$

Step-by-step explanation:

Given values are

$\sin \alpha=\frac{7}{25}$

$\cos \beta=\frac{2}{5}$

$\sin^2x+\cos^2=1$

$\cos \alpha=\sqrt{1-\sin^2\alpha}$

$\cos \alpha=\sqrt{1-(\frac{7}{25})^2}$

$\cos \alpha=\sqrt{1-\frac{49}{625}}$

$\cos \alpha=\sqrt{\frac{576}{625}}$

$\cos \alpha=\frac{24}{25}$

$\sin \beta=\sqrt{1-\cos^2\beta}$

$\sin \beta=\sqrt{1-(\frac{2}{5})^2}$

$\sin \beta=\sqrt{1-\frac{4}{25}}$

$\sin \beta=\frac{\sqrt{21}}{5}$

$\cos(\alpha-\beta)=\cos\alpha\cos\beta+\sin\alpha\sin\beta$

$\cos(\alpha-\beta)=\frac{24}{25}\times\frac{2}{5}+\frac{7}{25}\times\frac{\sqrt{21}}{5}$

$\cos(\alpha-\beta)=\frac{48+7\sqrt{25}}{125}$

7 0

3 years ago

A nature museum has 2008 specimens of early birds, some with 222 wings and some with 444 wings. The specimens have a total of 40

ludmilkaskok [199]

Let's assume

number of birds with 2 wings is x

number of birds with 4 wings is y

A nature museum has 2008 specimens of early birds

so,

$x+y=2008$

Total of wings of 2 wings bird =2x

Total of wings of 4 wings bird =4y

The specimens have a total of 4384 wings

so, we get

$2x+4y=4384$

we can divide both sides by 2

$x+2y=2192$

so, we get system of equations as

$x+y=2008$

$x+2y=2192$

we can solve for x and y

We can subtract both equations

$2008-y+2y=2192$

$y=184$

$x=2008-184$

$x=1824$

$y=184,\:x=1824$

so,

number of birds with 2 wings is 1824

number of birds with 4 wings is 184.............Answer

5 0

3 years ago

Least to greatest 0.4, 5/8, 74%, 3/5

SashulF [63]

Answer:

0.4,3/5,5/8,74%

Step-by-step explanation:

Change them all into decimals.

Get 0.4,0.625,0.74,0.6

Then reorder and see what their original values were

5 0

3 years ago

Y<=x-5, and y<=-x-4 would be points (1,10)? or (-1,10) (10,1) 1,-10)

weeeeeb [17]

It would be (1,-10) <===

4 0

3 years ago

Find the value of x in the triangle shown below. = २० 14 14 50° 18

Alexandra [31]

Answer:

x = 87

Step-by-step explanation:

37 + 56 = 93

triangles always equal to 180

180 - 93 = 87

5 0

2 years ago