1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
sergij07 [2.7K]
3 years ago
7

If cos x= 5/13 and sin x <0 find cos (x/2) and sin (2x)

Mathematics
1 answer:
taurus [48]3 years ago
4 0
We know that

if cos x is positive
and
sin x is negative
so
the angle x belong to the IV quadrant

cos x=5/13
we know that
sin²x+cos²x=1-------> sin²x=1-cos²x------> 1-(5/13)²---> 144/169
sin x=√(144/169)-------> sin x=12/13
but remember that x is on the IV quadrant
so
sin x=-12/13

Part A) <span>cos (x/2)
cos (x/2)=(+/-)</span>√[(1+cos x)/2]
cos (x/2)=(+/-)√[(1+5/13)/2]
cos (x/2)=(+/-)√[(18/13)/2]
cos (x/2)=(+/-)√[36/13]
cos (x/2)=(+/-)6/√13-------> cos (x/2)=(+/-)6√13/13
the angle (x/2) belong to the II quadrant
so
cos (x/2)=-6√√13/13

the answer Part A) is 
cos (x/2)=-6√√13/13

Part B) sin (2x)
sin (2x)=2*sin x* cos x------> 2*[-12/13]*[5/13]----> -120/169

the answer Part B) is 
sin(2x)=-120/169
You might be interested in
A truck driver travels 93 miles in one hour and 30 minutes at this rate how far will he travel in four hours
sdas [7]
<h3>Answer: 248 miles</h3>

======================================================

Work Shown:

1 hr, 30 min = 1 hr + 30/60 hr

1 hr, 30 min = 1 hr + 0.5 hr

1 hr, 30 min = 1.5 hr

The driver travels 93 miles in 1.5 hours, so his speed is

rate = distance/time

r = d/t

r = 93/1.5

r = 62 mph

In four hours, he travels

d = r*t

d = 62*4

d = 248 miles

---------------

An alternative method is shown below

(93 miles)/(1.5 hrs) = (x miles)/(4 hours)

93/1.5 = x/4

93*4 = 1.5*x ..... cross multiply

372 = 1.5x

1.5x = 372

x = 372/1.5

x = 248

5 0
3 years ago
Read 2 more answers
Orville staples is a painter who earns 30,000 a year. he is single and claims 3 allowances
babunello [35]

Using the information in the table given, the Gross pay, deductions and net pay for Orville staples are :

  • $30,000
  • $2340
  • $1860
  • $600
  • $450
  • $34.50
  • $15.00
  • $24700.50

Given the tax time table :

  • Social security tax = 6.2% of $97,500
  • Medicare = 1.45% of gross income
  • State tax = 2% of gross pay
  • Local tax = 1.5% of gross pay
  • Gross pay = $30,000

1.) Gross pay, total amount earned prior to tax = $30,000

2.) <u>Using the weekly payroll for singles</u> :

Number of weeks in a year = 52

Weekly earning = 30000/52 = 600

The Federal income tax = $25 per week  (3 allowances claimed)

Total FIT = $45 × 52 = $2340

3.) <u>Social security tax</u> :

SS tax = 6.2% × $30,000 = $1860

4.) <u>State tax</u> :

2% of gross pay

2% × $30,000 = $600

5.) <u>Local tax</u> :

1.5% × 30,000 = $450

6.) <u>Medical dues</u>  = $34.50

7.) <u>Others</u> : = $15.00

8.) <u>Net pay = Gross pay - Total deduction</u>

Net pay = 30000 - $(2340+1860+600+450+34.50+15)

Net pay = 30,000 - 5299.50 = $24700.50

Learn more :brainly.com/question/24919039

8 0
3 years ago
Can u pls help me with this question
ziro4ka [17]

Step-by-step explanation:

I am not sure bout this question sry

you reap what you sow ;)

6 0
3 years ago
The vertices of a rectangle are Q (2, -3), R (2,4), S (5,4), and T (5, -3).
disa [49]

4) A_{QRST} = A_{Q'R'S'T'} = 9.

5) The areas of the rectangles QRST and Q'R'S'T' are the same since the translation of the <em>geometric</em> loci conserved the <em>Euclidean</em> distance.

6) x = 1, w = 3, y = - 1/4, z = 1/3

<h3>How to analyze and apply rigid transformations</h3>

<em>Rigid</em> transformations are transformations applied on <em>geometric</em> loci such that <em>Euclidean</em> distance is conserved. In this question we have applications of translations, a kind of <em>rigid</em> transformation.

Exercise 4

In this part we must determine the areas of rectangles QRST and Q'R'S'T':

Rectangle QRST

A = RS · QT

A = 3 · 3

A = 9

Rectangle Q'R'S'T'

Q'(x, y) = (2, - 3) + (- 3, - 3)

Q'(x, y) = (- 1, - 6)

R'(x, y) = (2, 4) + (- 3, - 3)

R'(x, y) = (- 1, 1)

S'(x, y) = (5, 4) + (- 3, - 3)

S'(x, y) = (2, 1)

T'(x, y) = (5, - 3) + (- 3, - 3)

T'(x, y) = (2, - 6)

A = R'S' · Q'T'

A = 3 · 3

A = 9

The rectangles QRST and Q'R'S'T' have both an area of 9 square units.

Exercise 5

The areas of the rectangles QRST and Q'R'S'T' are the same since the translation of the <em>geometric</em> loci conserved the <em>Euclidean</em> distance.

Exercise 6

In this case, we must solve the following equations:

PQ = A'(x, y) - A(x, y)

(4, 1) = (2 · x + 1, 4) - (- 1, w)

(4, 1) = (2 · x + 2, 4 - w)

(4, 1) = (2 · x, - w) + (2, 4)

(2, - 3) = (2 · x, - w)

(x, w) = (1, 3)

PQ = B'(x, y) - B(x, y)

(4, 1) = (3, 3 · z) - (8 · y - 1, 1)

(4, 1) = (2 - 8 · y, 3 · z)

(4, 1) = (- 8 · y, 3 · z) + (2, 0)

(2, 1) = (- 8 · y, 3 · z)

(y, z) = (- 1/4, 1/3)

To learn more on translations: brainly.com/question/17485121

#SPJ1

3 0
2 years ago
a team of five is chosen from seven men and five women to work on a special project. in how many ways can the team be chosen to
tiny-mole [99]

Answer:

210 ways.

Step-by-step explanation:

The number of ways to choose 3 women from 5 is 5C3 = 5! / 3!2!

= 10 ways.

The number of ways to choose 2 men form 7 = 7C2 =  7! / 5!2! =   21 ways.

So the number of ways of choosing the team of 5 = 10 * 21 = 210 ways.

7 0
3 years ago
Other questions:
  • Work out 4/5 - 1/2 :):):)
    9·1 answer
  • What is the slope to the equation (2,1) (-1,-2)
    14·2 answers
  • Factor the polynomial expression 4x2 +9.
    10·1 answer
  • 7. If line I is parallel to line m and angle 8 = 109°, what is angle 5?​
    10·1 answer
  • Simplify the expression 2.75j + 2.25 - 1.5j + 3
    7·1 answer
  • Judy uses 12 tiles to make a mosaic. 8 of the tiles are blue. what fraction ,in simplest form, represents the tiles that are blu
    15·1 answer
  • a. 5) Nevaeh deposits $1,500 into each of two savings accounts: Account I earns 5% annual simple interest. b. Account II earns 5
    15·1 answer
  • VALUE OF X PLEASE ASAP
    7·1 answer
  • Pls help me asap !!!!!
    13·1 answer
  • Tyesha needs 15.75 feet of wood for a project. She has lengths of wood that are 7.5 feet, 5.25 feet, and 6.75 feet long. Does Ty
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!