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3 years ago

Which of the following are identities? Check all that apply.

Mathematics

2 answers:

Genrish500 [490]3 years ago

7 0

Answer:

B and C and D

Step-by-step explanation:

This will help,

Ivenika [448]3 years ago

7 0

Answer:

Options A and D.

Step-by-step explanation:

To check the identities we have to check each option given.

A. tan(x - π) = tanx

We take left hand side (L.H.S.) of the equation.

tan(π - x) = tanx [ since we know tan(π ± x) = tanx ]

So L.H.S. = R.H.S.

It's an identity.

B. sin(x + y) + sin(x - y) = 2cosx siny

We take L.H.S. first

sin(x + y) + sin(x - y)

= sinx coxy + siny cosx + sinx cosy - cosx siny

= 2sinx cosy ≠ R.H.S.

Option B is not an identity.

C. cos(x + y) - cos(x - y) = 2cosx cosy

We take L.H.S. of the equation.

cos(x + y) - cos(x - y) = cosx cosy - sinx siny - (cosx cosy + sinx siny)

= -2sinx siny ≠ R.H.S.

Therefore, option C is not an identity.

D. cos(x + y) + cos(x - y) = 2cosx cosy

We take L.H.S. of the equation.

cos(x + y) + cos(x - y) = cosx cosy - sinx siny + cosx cosy + sinx siny

= 2cosx cosy = R.H.S.

Therefore, option D is an identity.

Options A and D are the identities.

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The longest side of an acute isosceles triangle is 12 centimeters, Rounded to the nearest tenth, what is the

vodomira [7]

Answer:

8.5

Step-by-step explanation:

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2 years ago

Alice purchased 4 1⁄2 kilograms of olive oil for $27. What is the price per kilogram?

Ede4ka [16]

<h3>Answer: 6 dollars per kilogram</h3>

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

Explanation:

The mixed number 4 & 1/2 converts to the decimal form 4.5

The unit price is 27/(4.5) = 6 dollars per kilogram

------

If you wanted, you can think of it like this ratio

4.5 kg : 27 dollars

Dividing both parts of that ratio by 4.5 will lead to

1 kg : 6 dollars

8 0

2 years ago

Jeff has a density of 1000 g/mL and a volume of 25-mL. What is Jeff’s mass?

zlopas [31]

Answer:

25,000 grams

Step-by-step explanation:

Density can be found using the following formula:

$d=\frac{m}{v}$

If we rearrange the formula for $m$ , mass, we will multiply both sides of the equation by v.

$d*v=\frac{m}{v}*v$

$d*v=m$

The mass can be found by multiplying the density by the volume.

Jeff's density is 1000 grams per milliliter and his volume is 25 milliliters.

$d= 1000 g/mL\\v=25 mL$

Substitute the values into the formula.

$m=d*v$

$m= 1000 g/mL * 25 mL$

Multiply. When you multiply, the "mL" or milliliters will cancel out.

$m= 1000 g * 25$

$m= 25000 g$

Jeff's mass is 25,000 grams.

6 0

3 years ago

Can someone help me plz

joja [24]

is it from a textbook

7 0

3 years ago

Figure ABCD is a parallelogram. If point C lies on the line y= -1, what is the x-value or point C?

MrRa [10]

Answer:

The correct answer is option D. 4

Step-by-step explanation:

Points to remember

Opposite sides of the parallelogram are equal.

From the figure we can see that,AB and CD are opposite sides.

Therefore AB = CD

<u>To find the length of AB</u>

From the figure we get, AB = 4 units

Therefore CD = 4 units

<u>To find the x coordinate of point C</u>

y coordinate is -1

x coordinate is 4 units from point D

x coordinate of D is 0, therefore x coordinate of C = 0 + 4 = 4

The correct answer is option D. 4

4 0

3 years ago

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