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SashulF [63]
3 years ago
10

Solve for x

Mathematics
1 answer:
jekas [21]3 years ago
5 0

option C is correct......

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What is this shape called
gizmo_the_mogwai [7]

Answer:

curved ramp

or quadrant circle map

Step-by-step explanation:

3 0
3 years ago
Read 2 more answers
Could someone please help me:) I am stick and I am not sure what to do ​
Delicious77 [7]

Answer:

Part 5.1.1:

\displaystyle \cos 2A = \frac{7}{8}

Part 5.1.2:

\displaystyle \cos A = \frac{\sqrt{15}}{4}

Step-by-step explanation:

We are given that:

\displaystyle \sin 2A = \frac{\sqrt{15}}{8}

Part 5.1.1

Recall that:

\displaystyle \sin^2 \theta + \cos^2 \theta = 1

Let θ = 2<em>A</em>. Hence:

\displaystyle \sin ^2 2A + \cos ^2 2A = 1

Square the original equation:

\displaystyle \sin^2 2A = \frac{15}{64}

Hence:

\displaystyle \left(\frac{15}{64}\right) + \cos ^2 2A = 1

Subtract:

\displaystyle \cos ^2 2A = \frac{49}{64}

Take the square root of both sides:

\displaystyle \cos 2A = \pm\sqrt{\frac{49}{64}}

Since 0° ≤ 2<em>A</em> ≤ 90°, cos(2<em>A</em>) must be positive. Hence:

\displaystyle \cos 2A = \frac{7}{8}

Part 5.1.2

Recall that:

\displaystyle \begin{aligned}  \cos 2\theta &= \cos^2 \theta - \sin^2 \theta \\ &=   1- 2\sin^2\theta \\ &= 2\cos^2\theta - 1\end{aligned}

We can use the third form. Substitute:

\displaystyle \left(\frac{7}{8}\right) = 2\cos^2 A - 1

Solve for cosine:

\displaystyle \begin{aligned} \frac{15}{8} &= 2\cos^2 A\\ \\ \cos^2 A &= \frac{15}{16} \\ \\ \cos A& = \pm\sqrt{\frac{15}{16}} \\ \\ \Rightarrow \cos A &= \frac{\sqrt{15}}{4}\end{aligned}

In conclusion:

\displaystyle \cos A = \frac{\sqrt{15}}{4}

(Note that since 0° ≤ 2<em>A</em> ≤ 90°, 0° ≤ <em>A</em> ≤ 45°. Hence, cos(<em>A</em>) must be positive.)

4 0
3 years ago
Which are the solutions of x2 = –7x – 8?
Yanka [14]
You can start by rewriting the equation so that the right side equals zero. Add -7x and 8 to both sides.

x^2+7x+8=0

You can now use the quadratic equation (below), where a=1, b=7, and c=8, to find solutions. Plug in these values for a, b, and c into the equation and simplify.

\frac{-b \pm \sqrt{b^2-4(ac)}} {2a}
\frac{-7 \pm \sqrt{7^2-4(1 \times 8)}} {2 \times 1}
\frac{-7 \pm \sqrt{49-32}} {2}
\frac{-7 \pm \sqrt{17}} {2}

The final answer is the combination of both solutions.
x=\frac{-7}{2} \pm \frac{\sqrt{17}} {2} \approx -3.5 \pm 2.06.

Or approximately...
x=(-3.5-2.06) \approx -5.56, (-3.5+2.06) \approx-1.44
8 0
3 years ago
Read 2 more answers
a car is travelling at x kilometres per hour find the cars speed, in terms of x in metres per second give your answer in its sim
andrey2020 [161]
Its distance divided by time takrn × 60
7 0
3 years ago
When Gabby went food shopping, she spent $14.90 on 5 bags of marshmallows to make Rice Krispie treats. She has to go to the stor
dusya [7]

the answer is $20.70


3 0
3 years ago
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