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3 years ago

15

Write the value of

- 2 \cos {}^{2} c" alt="1 - 2 \cos {}^{2} c" align="absmiddle" class="latex-formula">

1 answer:

enot [183]3 years ago

6 0

Step-by-step explanation:

1-2cos²c.

> (cos²c+sin²c)-2cos²c. (cos²c+sin²c=1)

> cos²c+sin²c-2cos²c

> sin²c-cos²c.

is your correct answer.

hope this helps you.

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Glenn needs to cut pieces of a lanyard that are each 1 meter long to make lanyard key chains. If he has 3 pieces of lanyard that

Novosadov [1.4K]

Answer:

30

Step-by-step explanation:

3 pieces each 1 dekameter long

1 dekameter = 10 meters

Convert dekameters to meters

3 pieces each 10 meters long

Multiply

Glenn has 30 meters of lanyard

Divide

He can cut 30 1-meter pieces

Hope this helps :)

3 0

3 years ago

Could someone help me rnnn?

GuDViN [60]

Answer:

vertex = (0, -4)

equation of the parabola: $y=3x^2-4$

Step-by-step explanation:

Given:

y-intercept of parabola: -4
parabola passes through points: (-2, 8) and (1, -1)

Vertex form of a parabola: $y=a(x-h)^2+k$

(where (h, k) is the vertex and $a$ is some constant)

Substitute point (0, -4) into the equation:

$\begin{aligned}\textsf{At}\:(0,-4) \implies a(0-h)^2+k &=-4\\ah^2+k &=-4\end{aligned}$

Substitute point (-2, 8) and $ah^2+k=-4$ into the equation:

$\begin{aligned}\textsf{At}\:(-2,8) \implies a(-2-h)^2+k &=8\\a(4+4h+h^2)+k &=8\\4a+4ah+ah^2+k &=8\\\implies 4a+4ah-4&=8\\4a(1+h)&=12\\a(1+h)&=3\end{aligned}$

Substitute point (1, -1) and $ah^2+k=-4$ into the equation:

$\begin{aligned}\textsf{At}\:(1.-1) \implies a(1-h)^2+k &=-1\\a(1-2h+h^2)+k &=-1\\a-2ah+ah^2+k &=-1\\\implies a-2ah-4&=-1\\a(1-2h)&=3\end{aligned}$

Equate to find h:

$\begin{aligned}\implies a(1+h) &=a(1-2h)\\1+h &=1-2h\\3h &=0\\h &=0\end{aligned}$

Substitute found value of h into one of the equations to find a:

$\begin{aligned}\implies a(1+0) &=3\\a &=3\end{aligned}$

Substitute found values of h and a to find k:

$\begin{aligned}\implies ah^2+k&=-4\\(3)(0)^2+k &=-4\\k &=-4\end{aligned}$

Therefore, the equation of the parabola in vertex form is:

$\implies y=3(x-0)^2-4=3x^2-4$

So the vertex of the parabola is (0, -4)

5 0

3 years ago

Read 2 more answers

What is the equation of the line that passes through (-3, -1) and has a slope of 3/5 ? Put your answer in slope-intercept form.

Verizon [17]

Slope-intercept form: y = mx + b

m = the slope

b = y-intercept.

In this problem,

m = 3/5

b = ?

So far y = 3/5x + b

Let's plug the point (-3, -1) into our slope equation.

-1 = 3/5(-3) + b

Simplify the right side.

-1 = -9/5 + b

Add 9/5 to both sides.

4/5 = b

The equation is: y = 3/5x + 4/5

Answer choice A is correct.

6 0

3 years ago

What is the equation of a circle with center (5, -8) and diameter 4?

klio [65]

Answer:

is 8 porque s mi nose maje

6 0

3 years ago

Use a common denominator to write an equivelent fractions for each fraction.

sergejj [24]

Sorry for not giving you the calculation here -

5/12 and 2/9 have denominators divisible by only 3 right? Well The common denominator that can then change is 3 because that's the only number they have in common (except 1)

8 0

3 years ago