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3 years ago

PLEASE I REALLY NEED HELP

Mathematics

1 answer:

skad [1K]3 years ago

7 0

Shii I don’t know that one there bud

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Rewrite with only sin x and cos x.

Annette [7]

Option A

$\cos 3 x=\cos x-4 \cos x \sin ^{2} x$

<em><u>Solution:</u></em>

Given that we have to rewrite with only sin x and cos x

Given is cos 3x

$cos 3x = cos(x + 2x)$

We know that,

$\cos (a+b)=\cos a \cos b-\sin a \sin b$

Therefore,

$\cos (x+2 x)=\cos x \cos 2 x-\sin x \sin 2 x$ ---- eqn 1

We know that,

$\sin 2 x=2 \sin x \cos x$

$\cos 2 x=\cos ^{2} x-\sin ^{2} x$

Substituting these values in eqn 1

$\cos (x+2 x)=\cos x\left(\cos ^{2} x-\sin ^{2} x\right)-\sin x(2 \sin x \cos x)$ -------- eqn 2

We know that,

$\cos ^{2} x-\sin ^{2} x=1-2 \sin ^{2} x$

Applying this in above eqn 2, we get

$\cos (x+2 x)=\cos x\left(1-2 \sin ^{2} x\right)-\sin x(2 \sin x \cos x)$

$\begin{aligned}&\cos (x+2 x)=\cos x-2 \sin ^{2} x \cos x-2 \sin ^{2} x \cos x\\\\&\cos (x+2 x)=\cos x-4 \sin ^{2} x \cos x\end{aligned}$

$\cos (x+2 x)=\cos x-4 \cos x \sin ^{2} x$

Therefore,

$\cos 3 x=\cos x-4 \cos x \sin ^{2} x$

Option A is correct

7 0

3 years ago

A basketball coach will select the members of a five-player team from among 9 players, including John and Peter. If the five pla

vivado [14]

Answer:

Step-by-step explanation:

Given that a basketball coach will select the members of a five-player team from among 9 players, including John and Peter.

Out of nine players five are chosen at random.

The team consists of John and Peter.

Hence we can sort 9 players as I group, John and Peter and II group 7 players.

Now the selection is 2 from I group and remaining 3 from II group.

Hence no of ways of selecting a team that includes both John and Peter= $2C2*7C3$ =35

Total no of ways = $9C5$ =126

= $\frac{2C2*7C3}{9C5}$ = $\frac{35}{126} =\frac{5}{18}$

6 0

3 years ago

How do you write 3 2/4 as a fraction greater t hff an 1

elena55 [62]

Answer:

Step-by-step explanation:

Hope this helps 3 over 4 hope this helps

3 0

3 years ago

The graph of F(x) can be stretched vertically and flipped over the x-axis to produce the graph of G(x). If F(x)=x^2, which of th

vesna_86 [32]

To stretch it vertically, you'll need a coefficient greater than 1 in front of the x. If you want to flip the graph over the x axis that coefficient needs to be negative. So it can only be D

5 0

3 years ago

Read 2 more answers

A company loses $5,400 as the result of a manufacturing defect. Each of the 8 owners have agreed to contribute an equal amount,

vredina [299]

Answer:

A. 5400-8x

B. $600

Step-by-step explanation:

5400-8x=600

8x=5400-600

x=4800/8=600

5 0

3 years ago