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
Liula [17]
3 years ago
15

PLEASE HELP!!! I don’t understand

Mathematics
1 answer:
asambeis [7]3 years ago
3 0

Answer:

Step-by-step explanation:

Use the half angle identity for cosine:

cos(x/2)=+ or - sqrt(1+cos(x))/sqrt(2)

I'm going to figure out the sign part first for cos(x/2)...

so x is in third quadrant which puts x between 180 and 270

if we half x, x/2 this puts us between 90 and 135 (that's the second quadrant)

cosine is negative in the second quadrant

so we know that

cos(x/2)=-sqrt(1+cos(x))/sqrt(2)

Now we need cos(x)... since we are in the third quadrant cos(x) is negative...

If you draw a reference triangle sin(x)=3/5 you should see that cos(x)=4/5 ... but again cos(x)=-4/5 since we are in the third quadrant.

So let's plug it in:

cos(x/2)=-sqrt(1+4/5)/sqrt(2)

No one likes compound fractions (mini-fractions inside bigger fractions)

Multiply top and bottom inside the square roots by 5.

cos(x/2)=-sqrt(5+4)/sqrt(10)

cos(x/2)=-sqrt(9)/sqrt(10)

cos(x/2)=-3/sqrt(10)

Rationalize the denominator

cos(x/2)=-3sqrt(10)/10

You might be interested in
YA'LL I REALLY NEED HELP !!!!!! Which ordered pair is a solution to the system of inequalities? y ≤ x and y ≤ –2
pochemuha

Answer: C. (2, -4)

Step-by-step explanation:

Take into consideration that y is less than or equal to -2. The only option in which the y value is less than or equal to -2 is option C., thus C would correctly solve the system of inequalities.

4 0
3 years ago
Evaluate Ic2 + b2l, given a = 5, b = -3, and c= -2.
LenKa [72]

Answer:

Ic² + b²l = 13 units.

Step-by-step explanation:

We have to evaluate the expression Ic² + b²l with unknowns b and c and having the values of b and c respectively - 3 and - 2.

Now, Ic² + b²l

= I(- 2)² + (- 3)²l {Putting the values of b and c}

= I4 + 9l  

= I13l

= 13 units.

Therefore, Ic² + b²l = 13 units. (Answer)

5 0
3 years ago
What is the area of the shaded triangle inside the square? Round your answer to the nearest square inch.
PilotLPTM [1.2K]
Area of the triangle = 1/2 * base * <span>height 

base = 16 in
</span>height  = 16 in

Area = 1/2 * 16 * 16 = 128 in.
7 0
3 years ago
Read 2 more answers
Help! Please? The ratio (by volume) of milk in a certain solution is 3 to 8. If the total volume of the solution is 187 cubic fe
DIA [1.3K]
We know that the total volume of the solution is 187 cubic feet.
187=3x+8x
187=11x
17=x
Now we know that the ratio 3 to 8 is 51 to 136.
Double check, (3*17)+(8*17)=187.
I'm not sure which part of the ratio is water, but knowing this information, you should be able to solve it. I believe it may be this:
The total volume of milk is 51. If the rest of the solution is water, then 187-51=136.
6 0
3 years ago
A present is shaped like a
matrenka [14]

Answer: Yes

Step-by-step explanation:

8 0
3 years ago
Other questions:
  • What is -3 (x-8)=87​
    8·2 answers
  • Solve for x. 3(x + 2) + 4(x - 5) = 10
    15·1 answer
  • Which of the following has the lowest unit price?
    8·1 answer
  • louie has $1,000 and wants it to grew to $5,000 in 10 years,what compound interest rate does he need?
    11·1 answer
  • (HELP ASAP ILL GIVE BRAINIEST) <br> Graph h(x) = { x +4.
    9·1 answer
  • I have a few questions! what is the gcf for
    11·1 answer
  • Enter numbers into the table so that the paired values are in a proportional relationship. x 2 6 8 20 y 3 4 6 10
    11·2 answers
  • Paul can build a desk in 12
    6·1 answer
  • What is the solution to the system below? <br> x + 3y = 0<br> 2x - y = -7
    6·1 answer
  • Joe brought 17 packs of cola to a party, and each pack had 8 cans. Teresa brought 6 cans of juice. How many cans did they bring
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!