MATHEMATICS HIGH SCHOOL

Write the expression as the sine, cosine, or tangent of an angle.
sin 9x cos x - cos 9x sin x

Answers

Answer 1

Answer:

Answer:

$\sin (9x)\cos (x) - \cos 9(x) \sin (x)=\sin (8x)$

Step-by-step explanation:

Given : Expression $\sin (9x)\cos (x) - \cos 9(x) \sin (x)$

To find : Write the expression as the sine, cosine, or tangent of an angle?

Solution :

We know the trigonometry property of additional,

$\sin A\cos B-\cos A\sin B=\sin (A-B)$

On comparing the expression with property,

A=9x and B=x

Substitute in formula,

$\sin (9x)\cos (x) - \cos 9(x) \sin (x)=\sin (9x-x)$

$\sin (9x)\cos (x) - \cos 9(x) \sin (x)=\sin (8x)$

Therefore, The expression is written as the sine of an angle

$\sin (9x)\cos (x) - \cos 9(x) \sin (x)=\sin (8x)$

Answer 2

Answer: from sin(a-b) = sin(a)cos(b) - cos(a)sin(b)
let a=9x, b=x
sin(9x)cos(x) - cos(9x)sin(x) = sin(9x-x) = sin(8x)

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Which expression is equivalent to 64 – 9x^2?A(32)^2 – (3x)^2B(32)^2 + (-3x)2C(8)^2 – (3x)^2D(8)^2 + (-3x)^2
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Which two numbers add up to 7 and multiply to 6

Simplify.A.
–28xy

B.
–28

C.
28xy

D.
27

Answers

Your attachment says: (-1/2) · (4x) · (-2) · (7y) · (-1)

Let's put together the
1st, 3rd, and 5th factors: (-1/2) · (-2) · (-1) = -1

So now we have    (-1) · (4x) · (7y)

Well       (4x) · (7y) = (4 · 7) · (x · y) = 28 · x · y

So all together we have    (-1) · (28 · x · y) = -28xy

$\left(-(1)/(2)\right)(4x)(-2)(7y)(-1)\n\n=\left(-(1)/(2)\right)(-2)(4)(7)(-1)(x)(y)\n\n=(1)(4)(7)(-1)(xy)\n\n=(28)(-1)(xy)\n\n=(-28)(xy)\n\n=\boxed{-28xy}\to\boxed{\boxed{A}}$

Mr Castle shares out 54 marbles between Emily and jack the ration 5:1How much marbles does each child get?

Answers

Let's take the number of marbles given to Jack = x
Then, the marbles got by Emily will be 5 times that of Jack i.e. 5x
Then,
5x + 1x = 54
6x = 54
x = $(54)/(6)$

x = 9

So, number of marble Jack got = x = 9
And number of marbles Emily got = 5x = 5 * 9 = 45

$5x+x=54\n 6x=54\n x=9\n 5x=5\cdot9=45\n$

Emily - 45
Jack - 9

The famous irrational numbers

Answers

The most famous irrational number is pi because it pops up in so many different situations. Probably the next most famous one is 'e', the base of natural logarithms. The square root of 2 is also right up there.

Most famous would probably be pi because it goes on and on forever and it is most commonly used

Subtract 2F2Csixteen -92sixteen =

Answers

Choice-'B' is the correct choice . . . 2E9A .

I began converting the original numbers to decimal (base 10),
but decided that 5 points are not worth that much aggravation.

At that point, I wondered whether I could just write it down and
do it like any old other subtraction exercise. I've never done
that before with hex numbers, but I found that I could !

The only place you have to be extra careful is in the third place,
where you have to subtract '9' from '2'. In order to do that, you
have to borrow one from the 'F'. That makes the 'F' an 'E', and
it makes the '2' an '18', from which you can then easily subtract
the '9'. The difference of '2E9A' then jumps right out.

Thank you. I never knew you could just do that.

$2F2C-92=2E9A$

Y = 7 (15 + x)solve for x
How many minutes did you spend on a new song (x) if you practiced 210 minutes last week? 245 minutes? 315 minutes?

Answers

y equals the # of hours u practiced so u substitute y for the # of hours and then solve for x. if im right u multiply x times 7 and u get how many minutes per week u practice the new song. and just the x represents what u practice in a day 210=7(15+x) 210/7=15+x 30-15=x 15 min =x 245=7(15+x) 245/7=15+x 35-15=x 20=x 315=7(15+x) 315/7=15+x 45-15=x 30 min=x

Solve.: -2 1/3 -(-5) A:-7 1/3 B: 2 2/3 C: 3 2/3 D: 3 1/3