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4 years ago

WILL NAME BRAINLIEST!!!!!!!!!

Mathematics

1 answer:

san4es73 [151]4 years ago

6 0

Answer:

An example of an undefined term is a line. The undefined terms needed to define parallel lines are 'lines' and 'points.

Step-by-step explanation:

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2cos5xcos3x+sinx=cos8x

harkovskaia [24]

It looks like your equation (it's not an identity) is

2 cos(5x) cos(3x) + sin(x) = cos(8x)

Recall that

cos(x + y) = cos(x) cos(y) - sin(x) sin(y)

cos(x - y) = cos(x) cos(y) + sin(x) sin(y)

==> 2 cos(x) cos(y) = cos(x + y) + cos(x - y)

so that

2 cos(5x) cos(3x) = cos(8x) + cos(2x)

Then the equation simplifies to

cos(8x) + cos(2x) + sin(x) = cos(8x)

cos(2x) + sin(x) = 0

Also recall that

cos(2x) = 1 - 2 sin²(x)

so the equation is quadratic in sin(x) and can be factorized:

1 - 2 sin²(x) + sin(x) = 0

2 sin²(x) - sin(x) - 1 = 0

(2 sin(x) + 1) (sin(x) - 1) = 0

Solve for x :

2 sin(x) + 1 = 0 or sin(x) - 1 = 0

sin(x) = -1/2 or sin(x) = 1

[x = arcsin(-1/2) + 2nπ or x = π - arcsin(-1/2) + 2nπ] or x = arcsin(1) + 2nπ

(where n is any integer)

x = -π/6 + 2nπ or x = -5π/6 + 2nπ or x = π/2 + 2nπ

4 0

3 years ago

Help ASAP 6x - 3(2 – 3x)

guapka [62]

Answer:

First: we expand

6x-(6-9x)

Then we simplify

6x-6+9x

Collect like terms

(6x+9x)-6

Simplify:

15x-6

The answer is 15x-6

7 0

3 years ago

Read 2 more answers

I need some help with percentage word problems Please!!!

Gelneren [198K]

Answer:

1. $172.58

2. $421.12

3. ?

4. 14.69695%

5. ?

6. 8.33%

7. $288,767.5

I'm not sure how to find the answer to #3 and #5.

4 0

4 years ago

Mr. Morales purchases 6 boxes of pencils, 12 boxes of pens, and 4 cases of notebook paper for his classroom. Each box of pencils

Darina [25.2K]

Answer:

$522.60

Step-by-step explanation:

pencils: $4.10 * 6 ===> $24.60

pens: $6.50 * 12 ===> $78

notebook paper: $105 * 4 ===> $420

pencils + pens + notebook paper = total cost

24.60 + 78 + 420 = 522.60

5 0

3 years ago

Please help thank you

Scrat [10]

Question 1:

Use the Pythagorean theorem.

If $c^2\ \textless \ a^2+b^2$ , then the angle is acute.
If $c^2=a^2+b^2$ , then the angle is right.
If $c^2\ \textgreater \ a^2+b^2$ , then the angle is obtuse.

$a=18$
$b=80$
$c=81$

$c^2=6561$
$a^2+b^2=324+6400=6724$

$\boxed {c^2\ \textless \ a^2+b^2}$

Thus, the angle is acute.

Question 2:

Take the square root of the area to get the side length.

$\sqrt{200} = \sqrt{100*2} =10 \sqrt{2}$

That's the side length. Since we have a 45-45-90 right triangle if we divide the square across its diagonal, we just multiply the side length by the square root of 2 in order to get the diagonal length.

$10 \sqrt{2} * \sqrt{2}$
$=20$

Your answer is 20 m. Hope this helps! :)

7 0

4 years ago