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]
3 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]3 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
HELP ASAP!!!!! i wasted 30 points because i asked this question 3 times with no answer please.​
Effectus [21]
Your slope of this graph is: 4/3x
7 0
3 years ago
What is the minimum of the data?
BigorU [14]

Answer: the answer is 5

Step-by-step explanation:

I took the quiz

4 0
2 years ago
Cards are dealt, one at a time, from a standard 52-card deck. a if the first 2 cards are both spades, what is the probability th
ratelena [41]
So we already drew two cards and both of them are spades. So that means there are 50 cards and 11 spades left.

Then third card being spades would be 11 / 50

Now there are 10 spades and 49 cards left.
So the probability for fourth card would be 10 / 49

Fifth card would be 9 / 48.

So the probability of next three cards being spades would be
\dfrac{11}{50}\cdot\dfrac{10}{49}\cdot\dfrac9{48}=\dfrac{33}{3920}\approx\boxed{0.00842}

Hope this helps.
3 0
3 years ago
85,58,72,85,46,93 mean,mode,range,median​
Dima020 [189]

Answer:

mean= 73.167

mode= 85

range= 47

median​= 78.5

Step-by-step explanation:

46 58 72 85 85 93

mean= 73.167

mode= 85

range= 47

median​= 78.5

4 0
2 years ago
Read 2 more answers
Sarah was left with 35 pies after her bake sale. Her neighbor tookſ of the remaining pies. Sarah took home the rest. How many pi
aksik [14]

Answer:

Sarah took home 30 pies

Step-by-step explanation:

Given

Total remaining pieces of pies after bake sale left with Sarah = 35

Her neighbor took 1/7 of the remaining pies

Her neighbor took 1/7 * 35 = 5 pies

Hence, pieces of pies left with Sarah = 35 - 5 = 30

8 0
3 years ago
Other questions:
  • How to slove -8≤8+y for y
    5·1 answer
  • Give one combination of two factors whose product is 0.24, if one of the factors is a whole number greater than 1.
    13·2 answers
  • If x = 4, y = 2 and z = 1 then xz (4y - 2z) is
    5·1 answer
  • If 4 people each make a piece of dough and every 10days from each dough make 4 more; how many will there be after 20days
    13·1 answer
  • Christine went shopping and bought each of her eighteight nephews a​ gift, either a video costing​ $14.95 or a CD costing​ $16.8
    13·1 answer
  • Please please please please please help me I really need this
    13·2 answers
  • BRAINLIEST
    6·2 answers
  • -2x-y=0, where x≤0<br><br> Find the 6 trigonometric functions
    11·1 answer
  • What is equivlent to 3x+3[x+y]
    13·2 answers
  • Also this one--Sorry
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!