Here all the other ones .

Can someone please answer this for me

MaRussiya [10]

Answer:

BC = 1.7

Step-by-step explanation:

Since, cosine of any angle (except right angle) represents the ratio of base length and hypotenuse.

Cosθ = $\frac{\text{Base}}{\text{Hypotenuse}}$

From the given right triangle ΔACB,

$\text{Cos}(\angle B) = \frac{\text{Base}}{\text{Hypotenuse}}$

$=\frac{BC}{AB}$

Cos(70°) $=\frac{BC}{5}$

BC = 5Cos(70°)

= 1.71

≈ 1.7

8 0

3 years ago

2cos5xcos3x+sinx=cos8x

harkovskaia [24]

It looks like your equation (it's not an identity) is

2 cos(5x) cos(3x) + sin(x) = cos(8x)

Recall that

cos(x + y) = cos(x) cos(y) - sin(x) sin(y)

cos(x - y) = cos(x) cos(y) + sin(x) sin(y)

==> 2 cos(x) cos(y) = cos(x + y) + cos(x - y)

so that

2 cos(5x) cos(3x) = cos(8x) + cos(2x)

Then the equation simplifies to

cos(8x) + cos(2x) + sin(x) = cos(8x)

cos(2x) + sin(x) = 0

Also recall that

cos(2x) = 1 - 2 sin²(x)

so the equation is quadratic in sin(x) and can be factorized:

1 - 2 sin²(x) + sin(x) = 0

2 sin²(x) - sin(x) - 1 = 0

(2 sin(x) + 1) (sin(x) - 1) = 0

Solve for x :

2 sin(x) + 1 = 0 or sin(x) - 1 = 0

sin(x) = -1/2 or sin(x) = 1

[x = arcsin(-1/2) + 2nπ or x = π - arcsin(-1/2) + 2nπ] or x = arcsin(1) + 2nπ

(where n is any integer)

x = -π/6 + 2nπ or x = -5π/6 + 2nπ or x = π/2 + 2nπ

4 0

3 years ago

Evaluate: x(y – z) for x = 3, y = 9, and z = 2 O 33 O 45 O-21 O 21

ad-work [718]

Answer:

21

Step-by-step explanation:

Hi there!

We are given the expression x(y-z), and we want to evaluate it if x=3, y=9, and z=2

As we're given the values of the variables, we can substitute those values into the expression to find out what the value of the expression is.

So substitute 3 as x, 9 as y, and 2 as z in the expression above

x(y-z)

3(9-2)

Now we must follow the order of operations; start by subtracting 2 from 9 (do the stuff inside the parentheses first)

3(7)

Now multiply 3 and 7 together

21

Hope this helps!

3 0

3 years ago

Which of the following operations should be used first to solve 10t + 5 = 150.

My name is Ann [436]

Answer:

Subtract 5 to get 10t = 145.

3 0

3 years ago

Read 2 more answers

Quadrilateral ABCD is inscribed in a circle. Find the measure of each of the angles of the quadrilateral. Show your work.

Gemiola [76]

Sum of the angles of any quad =360
then y+(x+2)+(x-2)+(x-10) = y +3x -10 =360 (by adding both sides by 10)
y + 3x =370 ;.... eq 1
the sum of each two opposite sides in a quad inscribed in a circle =180
then (x+2)+(x-2)=180
therefore 2x =180
therefore x=90 (sub in eq 1)
y+3*90 =y +270 = 370 (subtracting both sides by 270)
therefore y=100
then measure angle B=100 degrees
A=92 degrees
C=88 degrees
D=80 degrees

8 0

3 years ago