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4vir4ik [10]
3 years ago
6

Can anyone help me with trig identities?

Mathematics
1 answer:
nevsk [136]3 years ago
6 0

Answer:

cosA = √(21/25)

Step-by-step explanation:

We know

sin²(A) + cos²(A) = 1

Next, we know that sin(A) = 2/5. Plugging that into our equation, we get

(2/5)² + cos²A = 1

4/25 + cos²A = 1

subtract 4/25 from both sides to isolate cos²A

cos²A = 1 - 4/25 = 25/25-4/25 = 21/25

square root both sides to get

cosA = √(21/25)

We do not include -√(21/25) in our possible answer for cosA because this is in quadrant 1, so cosA must be positive.

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Which point satisfies the system of equations y = 3x − 2 and y = -2x + 3?
Sedbober [7]

Answer:

(1,1)

Step-by-step explanation:

The choices are not visible, however are unnecessary to solve this problem.

Given y = 3x - 2 and y = -2x + 3

[Set them equal to each other]

3x - 2 = -2x + 3

[Find x]

3x + 2x - 2 = 3

3x + 2x = 5

5x = 5

x = 1

[Plug x = 1 to both equations to check and find y]

y = 3x - 2

y = 3(1) - 2 = 3 - 2 = 1

y = -2x + 3

y = -2(1) + 3 = -2 + 3 = 1

Both are equal to y = 1 when x = 1

The point is then: (1,1)

3 0
3 years ago
Read 2 more answers
Nick was surveying his field and saw some cows and ducks. Nick counted a total of 80 heads and
Natali [406]

Answers:

  • Total equation:  x+y = 80
  • Legs equation:  2x+4y = 248
  • How many ducks? 36
  • How many cows? 44

====================================================

Further explanation:

  • x = number of ducks
  • y = number of cows

x+y = 80 is the total equation (ie the head count equation) since we assume each animal has 1 head, and there are 80 heads total.

That equation can be solved to y = 80-x after subtracting x from both sides.

The legs equation is 2x+4y = 248 because...

  • 2x = number of legs from all the ducks only
  • 4y = number of legs from all the cows only
  • 2x+4y = total number of legs from both types of animals combined

We're told there are 248 legs overall, so that's how we ended up with 2x+4y = 248

------------

Let's plug y = 80-x into the second equation and solve for x.

2x+4y = 248

2x+4( y ) = 248

2x+4( 80-x ) = 248

2x+320-4x = 248

-2x+320 = 248

-2x = 248-320

-2x = -72

x = -72/(-2)

x = 36

There are 36 ducks

Now use this x value to find y

y = 80-x

y = 80-36

y = 44

There are 44 cows.

------------

Check:

36 ducks + 44 cows = 80 animals total

36*2 + 44*4 = 72 + 176 = 248 legs total

The answers are confirmed.

5 0
2 years ago
Integer operations <br> 11. -60<br> 12. 10<br> 13. -9<br> 14. 14<br> 15. 37
vlada-n [284]

Answer:

11. - 60 =  - 49 \\ 12.10 = 12.1 \\ 13. - 9 = 4 \\ 14.14 =  \frac{707}{50}  \\ 15.37 =  \frac{1537}{100}

3 0
3 years ago
What is the slope of the line that passes through the points (−10,−4) and (10, -29)?
OleMash [197]

Answer:

slope= - 5/4

Step-by-step explanation:

3 0
3 years ago
A test was marked out of 80. A boy scored 60% of the marks on the test. How many marks did he score?
cricket20 [7]
He score 48 marks.

This can be found by simply multiplying 80 by 60% (0.6). This will give you your rinal answer of 48.

I hope this helps!
7 0
3 years ago
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