# Trig. Law of Cosines

9,827 results

Math - Trig
What familiar formula can you obtain when you use the third form of the Law of Cosines c^2 = a^2 + b^2 - 2ab cos C and you let C = 90deg? What is the relationship between the Law of Cosines and this formula?

Trig
Should the triangle be solved beginning with Law of Sines of Law of Cosines. Then solve the triangle. Round to the nearest tenth. a=16, b=13, c=10. Cosines A=93 degrees, B=54 degrees, C=33 degrees

Trig. Law of Cosines
Show that any triangle with standard labeling... a^2+b^2+c^2/2abc = cos(alpha)/a + cos(beta)/b + cos(gamma)/c I don't get it. Can someone please help me. Start here with the law of cosines: a^2 = b^2 + c^2 -2bc Cos A b^2 = a^2 + c^2 -2ac Cos B c^2 = a^2 + b^2 - 2ab Cos C Add ...

Trig - Law of sines and cosines
ABC is an equilateral triangle with side length 4. M is the midpoint of BC, and AM is a diagonal of square ALMN. Find the area of the region common to both ABC and ALMN. I drew the diagram but I don't know how to find the answer? I think it has something to do with the law of ...

trig
I need to prove parallelogram law using the law of cosines. 2AB^2 + 2BC^2 = AC^2 + BD^2 Please, help me to do this.

Find the indicated angle è. (Use either the Law of Sines or the Law of Cosines, as appropriate. Assume a = 95 and c = 137(angle B=38). Round your answer to two decimal places.)

Math - Trig
Use the law of cosines to show that the measure of each angle of an equilateral triangle is 60deg. Explain your reasoning.

Trig
Use the Law of Cosines to determine the indicated angle θ. (Assume a = 17, b = 10, and c = 20. Round your answer to one decimal place.)

Trig-Medians and law of cosines and sines
In triangle ABC, we have AB=3 and AC=4. Side BC and the median from A to BC have the same length. What is BC? Not making sense to me, I think the answer must be simple, but I don't know how to solve I applied the law of sines but to no avail. Help is appreciated, thanks.

Trig
Should the triangle be solved beginning with Law of Sines of Law of Cosines. Then solve the triangle. Round to the nearest tenth. A=56 degrees, B=38 degrees, a=13. Sines. I get confused on the formula. I know C=86 degrees

Trig - check my answers plz!
1. (P -15/17, -8/17) is found on the unit circle. Find sinΘ and cosΘ Work: P= (-15/17, -8/17) cosΘ = a value P = (a,b) sinΘ = b value Answer: cosΘ = -15/17 sinΘ = -8/17 2. Should the triangle be solved beginning with Law of Sines or Law of Cosines...

law of cosines
law of cosines m<c=60, a=12,b=15 triangle

Precalculus
I know I posted this before,but I did not learn it your way .....instead I drew a picture and use the law of cosines....is there a way you can show me the work using law of cosines?? A plane flies 30 mi on a bearing of 200 degrees and then turns and flies 40 mi on a bearing of...

Calculus
A plane flying with a constant speed of 14 km/min passes over a ground radar station at an altitude of 7 km and climbs at an angle of 45 degrees. At what rate, in km/min is the distance from the plane to the radar station increasing 2 minutes later? I know you use law of ...

geometry
If a triangle has sides of lengths a and b, which make a C-degree angle, then the length of the side opposite C is c, where c2 = a2 + b2 − 2ab cosC. This is the SAS version of the Law of Cosines. Explain the terminology. Derive an equivalent SSS version of the Law of ...

Geometry
How do I find the mesurements of a isosceles triangle? I have the sides set as E=72 degrees, and the legs that come down are 15, and i have to find D and F..I have no clue how to do this. Or any idea of a formula to help with this. The two base angles are equal, and the sum of...

Trigonometry/Geometry - Law of sines and cosines
In most geometry courses, we learn that there's no such thing as "SSA Congruence". That is, if we have triangles ABC and DEF such that AB = DE, BC = EF, and angle A = angle D, then we cannot deduce that ABC and DEF are congruent. However, there are a few special cases in which...

Trig
Can you show us how to use law of cosines to show that theta equals inverse cosine of (a^2 + b^2 -484)/(2ab) where a^2=(7+xcos a)^2 + (28-xsin a)^2 and b^2=(7+xcos a)^2 + (xsin a -6)^2? Thanks

Algebra 2
Using the information given about a triangle, which law must you use to solve the triangle? Law of Sines, Law of Cosines, or Neither. ASA SSS SAS AAA SSA AAS

trigonometry
okay so in my review packet under the "calculator" section it says law of sines and law of cosines. i don't know what that means. i wikipedia-ed it but i don't understand what they are saying. Please help!

Trig.
I have answers for these problems, but I wanted to check if I had them right because I wasn't sure on some of them....Thanks. Solve the triangle: 1. a=4, b=8, alpha=30 deg. answer- beta=90 deg., gamma=60 deg., c=7 2. a=5, b=7, alpha=30 deg. answer- beta=44 deg., gamma=106 deg...

Physics
i was woundering if you could point in the right direction i'm looking for very easy physics topics that makes use of the law of sines or the law of cosines Thanks

math
solve each triangle using either the Law of Sines or the Law of Cosines. If no triangle exists, write “no solution.” Round your answers to the nearest tenth. A = 23°, B = 55°, b = 9 A = 18°, a = 25, b = 18

trig
Express sin4xcos3x as a sum or differences of sines and cosines

Trigonometry
Law of Cosines a=4.7 b=3.2 c=5.2 Find B

Maths/Right Triangle
There must be a relationship (formula) between the lengths of the sides of a Right Triangle and the angles opposite these sides. Help Please. Mike. Look at the law os sines or cosines. Law of sines a/sin(A) = b/sin(B) = c/sin(C) Law of cosines a2 = b2 + c2 - 2bc cos(A) b2 = c2...

Trig-Geometry - Law of sines and cosines
Hello everyone, I've been struggling on this problem for quite some time. It would be appreciated if you could help. Thanks. (The website is the diagram, it is a screenshot) In the diagram below, triangle ABC has been reflected over its median AM to produce triangle AB'C'. If ...

Pre-Calc Helppp!!!
Find the indicated angle è. (Use either the Law of Sines or the Law of Cosines, as appropriate. Assume a = 110 and c = 136 (angle B=38) Round your answer to two decimal places.)

law of cosines and sines
m<C=70,c=8,m<30 solve the triangle

precal 2
use the law of cosines to solve the triangle a=55, c=72, b=25

math
solve using law of sines or cosines A=?,B=51°,C=?,a=6m,b=?,c=7m

Pre calculus
Why is it dangerous to use the law of sines to find an angle but is not dangerous to use the law of cosines? Please explain this thoroughly.

Trigonometry
When using the Law of Cosines, how do I know if two triangles exist?

precal 2
use the law of cosines to solve the triangle A=55 degree, c=10, b=3

Math
a = 9, b = 3, and c = 11. Use the law of Cosines to solve B. My ans: 12.90 degs?

math
The law of cosines can't be used when which of the following combinations of information is given?

math
solving using the law of sines or cosines. a=75°,B=?,C=?,a=18cm,b=9cm,c=?

Math
Use the law of cosines to find the angle Q between the given vectors. v = 3i + j w = 2i - j

Math
Given the points A(0,0), B(4, 3) and C(2,9), what is the measure of angle ABC? Using Law of Cosines.

Pre-Cal
Use the law of cosines to find the angle of Q between the given vectors. v=3i + j w=2i - j

Trigonometry
Using the Law of Cosines, how can I show that the measure of each angle of an equilateral triangle is 60 degrees?

Math;);)
Use the vector form of the Law of Cosines to show that |u + v|^2 ≤ (|u| + |v|)^2 holds for any vectors u and v. What does this prove?

Calculus
Hello! I need help with this problem, its been irritating me for days! Any help would be greatly appreciated! Here’s the question.. The minute hand on a watch is 8 mm long and the hour hand is 4 mm long. How fast is the distance between the tip of the hands changing at 10:00...

Use the law of cosines to find the angle Q between the given vectors. v = 3i + j w = 2i - j

trig 26
simplify to a constant or trig func. 1. sec ²u-tan ²u/cos ²v+sin ²v change expression to only sines and cosines. then to a basic trig function. 2. sin(theta) - tan(theta)*cos(theta)+ cos(pi/2 - theta) 3. (sec y - tan y)(sec y + tan y)/ sec y combine fractions and simplify ...

trig/math
3. Draw vectors u and v tail-to-tail so that they make a è-degree angle. Draw the vector u − v, the third side of the triangle, and check to see that it points in the right direction. (a) Solve for cos è using the SSS version of the Law of Cosines, expressing all ...

geometry
I am studying for my GRE exam into grad school and it's been a very long time since I've done geometry. I have a problem to which I need to solve for the area of a triangle but I do not have the base. I do have all angles but I cannot remember how to convert angles into their ...

Law of cosines
A tree on a hillside casts a shadow 215 ft down the hill. If the angle of inclination of the hillside is 22 degree to the horizontal and the angle of elevation of the sun is 52 degreess, find the height of the tree. TIA sorry this is law of sines. sorry for the confusion.

Law of Cosines
i.imgur. com / CvoC1sB.jpg I'm confused about how to submit a link, but attached is the problem because there is a diagram. I did part of it, but I'm stuck! I put in spaces.

maths(direction cosines of vectors)
find the direction cosines of the vector joining the two points (4,2,2,) & (7,6,14) (this is new to me, used to think it was just one point not two.)

Alge2/trig
Should the triangle be solved beginning with Laws of Sines or Laws of Cosines. Then solve the triangle and round to the nearest tenth. a=16, b=13, c=10

Pre calculus
For the most part, will a law of cosines always be one triangle? As in one triangle to solve?

3 D - geometry (direction of cosines)
Find the angle between the lines between the lines whose direction cosines satisfy the equations l + m + n = 0 and 2mn + 3nl - 5lm =0.

Calculus
use law of cosines to show that theta equals inverse cosine of (a^2 + b^2 -484)/(2ab) where a^2=(7+xcos a)^2 + (28-xsin a)^2 and b^2=(7+xcos a)^2 + (xsin a -6)^2

Math
If a 14-ft ladder leans against a building, with an angle of elevation of 70°, how far up the building will the ladder reach? I believe this requires law of cosines but otherwise I am lost.

Math
Use the law of cosines to solve ABC with A=126.3, b=45, and c=62.5 I did all the work to find a but my problem is finding B a=96.2 Sin(B)=45sin126.3/96.2 B=Sin^-1(45sin126.3/96.2) It's not going through in my calculator

pre calc
the longest side of a triangle is 34 feet. the measures of two angles of the triangle are 40 and 65 degrees. find the lengths of the other two sides using law of sines and cosines

Math Work
I know that I'm using the Law of Cosines, but I'm confused on how to solve. I have to also round my answers to the nearest tenth for degrees and to the nearest hundredth for sides Given: A= 55 degrees b=3 c=10 Find: a= B= C=

Homework (Math)
I know that I'm using the Law of Cosines, but I'm confused on how to solve. I have to also round my answers to the nearest tenth for degrees and to the nearest hundredth for sides. Given: A= 55 degrees b=3 c=10 Find: a= B= C=

Algebra 2 with trigonometry
A baseball diamond is a square 90 feet on a side. The pitcher's mound is 60.5 feet from home. How far does the pitcher have to run to cover first? (we are using the LAW OF SINES AND COSINES)

Math
A ramp 10 feet in length rises to a loading Platform that is 4 feet off the ground. What is the angle of elevation of the ramp in degrees? Do I use the law of cosines? When I do though I'm getting a little confused what to do.

math
A ramp 10 feet in length rises to a loading Platform that is 4 feet off the ground. What is the angle of elevation of the ramp in degrees? Do I use the law of cosines? When I do though I'm getting a little confused what to do.

My Friend Needs Help With a Calc Problem.
how does five degrees east of north keep a plain going north when the wind pushes the plain four point six degrees west of north? This is not calculus. It is a vector problem. THe wind is pushing the plane west. If you need the solution, to find the direction of the wind, a ...

Calculating distance(law of cosines)
Observers P and Q are located on the side of a hill that is inclined 32 degrees to the horizontal as shown(picture given). The observer at P determines the angle of elevation to a hot air balloon to be 62 degrees. At the same instant the observer at Q measures the angle of ...

Math - Trig
Hi I have a Trig question that i don't understand, can someone please explain how to solve for it using cosine law?? A Clock with a radius of 15 cm has an 11 cm minute hand and a 7 cm hour hand. How far apart, to the nearest centimetre, are the tips of the hands at each time? ...

MATH
Using the Law of Cosines for vectors, give a vector proof that if quadrilateral ABCD is a rhombus, diagonal AC bisects <BAD. As part of your proof include a carefully drawn figure a statement of what is given, and a statement of what you are proving. I need help with this. ...

Math
A baseball diamond is a square sides 22.4 m. The pitcher's mound is 16.8 m from home plate on the line joining home plate and second base.. How far is the pitcher's mound from first base? (we are using the LAW OF SINES AND COSINES)

Precalc
A tower is supported by a guy wire 610 ft long. If the wire makes an angle of 69 degrees with respect to the ground and the distance from the point where the wire is attached to the ground and the tower is 125 feet. a) State if the law of sines or cosines should be used for ...

Pre-calc
prove the identity: (cosx)(tanx + sinx cotx)=sinx+cos(squared)x i need steps to show how i got the answer generally, it is a good idea to change all trig ratios to sines and cosines, and start with the more complicated-looking side. so.... LS = cosx(sinx/cosx + sinx(cosx/sinx...

geometry
Use the Law of Cosines to solve the problem. A ship travels due west for 83 miles. It then travels in a northwest direction for 111 miles and ends up 165 miles from its original position. To the nearest tenth of a degree, how many degrees north of west did it turn when it ...

MATH 112
two planes leave an airport at the same time. Their speeds are 320 miles per hour and 380 miles per hour. If the angle between their courses is 112 degrees, how far apart are they after two hours? (The hint is using the law of cosines)

Algebra II/ Trig
Should the triangle be solved beginning with Laws of Sines or Laws of Cosines. Then solve the triangle and round to the nearest tenth. a=16, b=13, c=10 I got this answer but it is wrong and don't understand where I made the mistake. a=16, b=13, c=10 a^2=b^2+c^2-2bc Cos A 16^2=...

Pre calculus
A tugboat is traveling at 30 miles per hour at a compass heading of 38 degrees. The current is from the direction of 125 degrees moving at 7 mph. Find the resultant speed and the direction of the boat. I understand the concept and that I must use the law of cosines. I got 30^2...

Physics
At the entrance channel of a harbor, the tidal current has a velocity of 4.94 km/hr in a direction 23.2° south of east. Suppose a ship caught in this current has a speed of 15.6 km/hr relative to the water. If the helmsman keeps the bow of the ship aimed north, what will be ...

government
Which branch of the law regulates wrongful acts involving injury to one’s person, property, or reputation in a situation not covered by the terms of a contract? A. common law B. tort law C. civil law D. contract law

government
Which branch of the law regulates wrongful acts involving injury to one's person, property, or reputation in a situation not covered by the term of a contract? A. common law B. tort law C. civil law D. contract law

math - trig
Why cant we solve an oblique triangle with the Law of Sines if we are given SAS?

bus law
What is the chronological order of the major legislation that makes up the history of employment law in this country? For each law, state the social problem the law was designed to address, and discuss how employment law has affected the workplace in the last two decades.

Science-Chemistry
1. What is Charles’s law? • State the definition of the law in words. • What are the assumptions of Charles’s law? • Write mathematical equations that represent the law. • What can you do with Charles’s law? • Using a gas-filled balloon as an example, describe ...

Math - Trig
Explain why we cannot solve an oblique triangle with the Law of Sines given SAS.

MATH!!!!
The CN Tower is 553m high. A person in a boat on Lake Ontario, at a point B due south of the tower, observes the top (T) of the tower at an angle of elevation of 8 degrees. At the same time, another person, at a point C on a bearing {S 85 degrees E } from the towerobserves an ...

Government Law question
What kind of law is it when judges make the law by their decisions on the bench? ___ Law

Trig
I was just wondering if anyone can explain the Law of Sines- "Ambiguity Case" to me, in a way that is easy to understand.

Law
Research and identify a labor law that is specific to your state. Share a brief summary of the law with us and discuss why you believe this law is or is not important to the employer-employee relationship.

trig
Use the Law of Sines to solve each triangle. P=110 degrees p=125, r=200 in triangel PQR

PreCalc - Vectors
An airplane is flying with an airspeed of 660 Kilometers per hour. The wind is blowing from 345 degrees at 35 km/h. What direction should the airplane take so that, with the wind, the plane will be flying in a direction of 72 degrees? I can compute airspeed and actual ...

precalculus
A force of 369 lbs makes an angle of 18 degrees 20 minutes with a force 427 lbs. Find the angle made by the equilibrant with the 369 lbs force. I know I can find this using the law of cosines, but I think my teacher wants me to use some vector thing, but I do not know how to ...

math
vector a is 8 ft., vector b is 2 ft, and theta is at 41 degrees. find the resultant and the direction. I drew a diagram that shows a connecting with b (head to tail), and they make the 41 degrees. I use law of cosines and got about 6ft, which doesn't sound right to me. my work...

legal and ethical issues
select a current or proposed law that impacts the delivery of human services what reliable resources are availiable to learn about the implications of this law? What is the purpose or rationale of the law? How will the law effect da-t-day operations within human service ...

science
An atom that has the same amount of atoms of each element on both sides of the reaction obeys what law? law of conservation of energy law of conservation of mass law of conservation of temperature law of conservation of atoms I know the Answer law of conservation of mass I ...

Physics
Two dogs pull horizontally on ropes attached to a post; the angle between the ropes is 65.0. Dog exerts a force of 256 and dog exerts a force of 344 . A) Find the magnitude of the resultant force. B) Find the angle the resultant force makes with dog 's rope. You can do this ...

calculus
A triangle ABC has sides of length AB = 3 inches and AC = 4 inches. Let t denote the angle at vertex A, and let s denote the length of the remaining side BC. If t increases at the rate of 2 radians per second, at what rate (in inches per second) does s change at the instant ...

Civics
In the case The Senate Of Tennessee V. John Thomas Scopes, high school biology teacher John Scopes was accused of teaching content that violated a Tennessee law that stopped public school teachers from teaching evolution. Scopes voted this law , but felt his right to free ...

Government
i think it is answer ( b ), can someone make sure What is the difference between criminal and civil law? a) There is no difference. b) The standard of guilt is higher in criminal law than it is in civil law c) The government is always involved in civil law but never in ...

Chemisrty
Determine which law is appropriate for solving the following problem. What volume will 1.56 liters of a gas at 27°C and 745 mmHg of pressure occupy at 100°C and 700 mmHg of pressure? Law used: Boyle's Law Charles' Law Combined Gas Law

bioethics
what is law natural law eternal law human positive law what is conscience different kinds of conscience pls need an answer thanks

Law
Hi there! I have totally got to find out how the Aussie Law is similar to the US law. Anyway I DO like know that like Oz follows England law mainly but that isn't what I need. Bushells of Thanks Minnie

what is the chronological order of the major legislation that makes up the history of employment law in this country? for each law, state the social problem the law was designed to address and whether the law has solved the problem.

Precalculus
In most geometry courses, we learn that there's no such thing as "SSA Congruence". That is, if we have triangles ABC and DEF such that AB = DE, BC = EF, and angle A = angle D, then we cannot deduce that ABC and DEF are congruent. However, there are a few special cases in which...

geometry
A segment that is a units long makes a C-degree angle with a segment that is b units long. In terms of a, b, and C, find the third side of the triangle defined by this SAS description. You have done numerical versions of this question. Start by finding the length of the ...

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