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almond37 [142]
3 years ago
9

Please answer quickly

Mathematics
1 answer:
Aleks04 [339]3 years ago
8 0

Answer:

<em> -√5/5</em>

Step-by-step explanation:

Given the following

sin(A) = 4/5

sinB - -2√5/5

SinA = 4/5 = opp/hyp

We can get cosA

opposite = 4

hypotenuse = 5

Adj = √5²-4² (pythagoras theorem)

Adj = √25-16

Adj = √9

Adj = 3

Cos A = Adj/hyp

Cos A = 3/5

Also

Sin B = -2√5/5 = opp/hyp

opposite = -2√5

hypotenuse = 5

Adj = √5²-(2√5)² (pythagoras theorem)

Adj = √25-20

Adj = √5

Cos B = Adj/hyp

Cos B =  √5/5

Evaluate cos (A-B)

cos (A-B) = cosAcosB + sinAsinB

cos (A-B) = 3/5(√5/5)+4/5(-2√5/5)

cos (A-B)  = 3√5/25 - 8√5/25

cos (A-B) = -5√5/25

cos (A-B) = -√5/5

<em>Hence the value of cos (A-B) is -√5/5</em>

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Alchen [17]

Answer:

that answer u put is correct and r u in K12 to lol

8 0
3 years ago
the sum of three numbers is 15. the second number is double the first. the third number is 5 less than the first. what are the t
tigry1 [53]

Hello from MrBillDoesMath!

Answer:

5, 10, 0

Discussion:

Let "f" be the first number. Then the questions tells us that

f + 2f  + (f-5) = 15           =>

f + 2f + f - 5 = 15            => add 5 to both sides

4f = 5+ 15 = 20              => divide both sides by 4

f = 20/4 = 5

The numbers as

f:        5

2f:     10

(f-5):  0

Thank you,

MrB

5 0
3 years ago
Answer...........................
Usimov [2.4K]

Answer:

9.9 years

Step-by-step explanation:

A = P e ^(rt)

Where A is the amount in the account

P is the amount invested

R is the interest rate

t is the time

P = 8500

r =7% = .07

A = 17000

Substituting into the equation

17000=8500 e^(.07t)

Divide each side by 8500

17000/8500=8500/8500 e^(.07t)

2 = e^(.07t)

Take the natural log of each side

ln (2) = ln e^(.07t)

ln(2) = .07t

Divide each side by .07

ln(2)/.07 = .07t/.07

ln(2)/.07 = t

9.902102579=t

Rounding to one decimal place

9.9 years

4 0
4 years ago
Read 2 more answers
Write 0.81 as a fraction in simplest from
Kazeer [188]

Answer:

81/100

Step-by-step explanation:

Here's how to convert 0.81 to a fraction...

There is not much that can be done to figure out how to write 0.81 as a fraction, except to literally use what the decimal portion of your number, the .81, means.

Since there are 2 digits in 81, the very last digit is the "100th" decimal place.

So we can just say that .81 is the same as 81/100.

So your final answer is: 0.81 can be written as the fraction 81/100

7 0
3 years ago
Are the ratios 14:18 and 7:9 equivalent
Pepsi [2]

Answer:

Yes

Step-by-step explanation:

14/18 equals 7/9

Dividing by two on the first ratio makes:

7/9 equals 7/9

4 0
3 years ago
Read 2 more answers
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