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
Sloan [31]
4 years ago
7

If cos x cos (pi/7)+sin x sin(pi/7)=-(sqrt 2)/2,then x can equal

Mathematics
1 answer:
Alex17521 [72]4 years ago
3 0
Main formula cos (a - b) =cosacosb + sina sinb
arccos(-x) = pi -arccosx

<span>cos x cos (pi/7)+sin x sin(pi/7) = cos(x-pi/7)

so </span>cos(x-pi/7) = -(sqrt 2)/2,  x -pi/7 = arc cos[-(sqrt 2)/2 ]= pi - arc cos[(sqrt 2)/2<span> ]

</span>arc cos[(sqrt 2)/2 ] = Pi/4 + 2kpi, and then x -pi/7 = pi - pi/4 +2kpi,
 implies x= -pi/7 + pi - pi/4 = -<span>pi/7 + 3pi/4 = -19pi/28 + 2kpi</span>
You might be interested in
The sum of two consecutive integers is 91. Find the integers.
Reil [10]

Answer:

Let the smaller integer be x and greater integer be (x+1)

x+(x+1)=91

2x+1=91

2x=91-1=90

x=90/2

x=45

7 0
2 years ago
Read 2 more answers
Can anyone get this answer
Doss [256]
This problem is asking you to apply the *Pythagorean Theorem*, given the information you’ve been given.

In case you’ve forgotten, the Pythagorean Theorem states that, in any given right triangle, the sum of the squares of the lengths of its legs is equal to the square of the length of its hypotenuse (the side opposite its right angle). If we call the lengths of the legs a and b, and the length of the hypotenuse c, this can be expressed in notation as a^2+b^2=c^2 (it doesn’t matter in this case which leg you pick for a and which you pick for b). Here, if we choose the left leg as a and the bottom leg as b, we’re given that a^2 (the area of a square with sides of length a) is 25 sq. in, and b is 3.5 in. Plugging those values into the equation, we have:

25 + (3.5)^2 = c^2

From here, you don’t even need to solve for c, you just need to find the value of c^2 (since you’re trying to find the area of a square with side lengths c). Just solve the left side of the equation, and you’ll have your answer in square inches.
























7 0
3 years ago
Pa help nmn po need lang po talaga
LekaFEV [45]

Answer:

Pa follow mona at pa brienlist

Step-by-step explanation:

Please

8 0
3 years ago
Evaluate -5 + 2 - 7 (-12) show work
Advocard [28]

Answer:

81

Step-by-step explanation:

4 0
3 years ago
Read 2 more answers
2x+1y=-9<br><br> Please help
xenn [34]

Answer:

x=-(9+1y)/2

y=-2x-9

Step-by-step explanation:

2x=-9-1y

x=-(9+1y)/2

-1y=2x+9

y=-2x-9

5 0
3 years ago
Other questions:
  • Yolanda buys two types of flowering plants. She buys 36 geraniums and 63 marigolds. She wants to plant an equal number of flower
    12·2 answers
  • Consider the equation 5x (2x + 1) - 3(2x + 1) = 0.
    11·1 answer
  • A=p(1+ r/n)nt
    9·1 answer
  • If the measures of the angles in the following triangle were listed in increasing order, which measure would be second? (2x+24)
    13·1 answer
  • What percent of 500 is 50?​
    13·2 answers
  • Find the difference: (6y3 + 17y − 3) − (4y3 − 11y + 9)
    8·2 answers
  • Max went to a shopping mall with $45 in his wallet. He spent 4/5 of the money he had in his wallet at the bookstore. How much mo
    15·1 answer
  • Find the derivative of sinx/1+cosx, using quotient rule​
    9·1 answer
  • What is the equation of the line that passes through the point (6,3) and has a slope of -1/3
    13·1 answer
  • A force of 72 N is applied to an area of 610 cm2.
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!