Does any one know what can The law of cosines be used for. Like in what kind of job.?
543112
Surveying,  we use it all the time
161223
law of cosines : a^2 = b^2 + c^2 -2bc * cos(A)\nwhere a, b,c are side lengths and A is the angle oppisite side a.
120816
Mainly in architecture (though computers do most of the work these days...).\nAlso, I have a friend who is an artist, and when she creates 3d work (sculptures, interactive art) she uses trigonometry and extremums to decide certain things (the best angle for a part of the work, how to use minimum material when she doesn't have a big budget etc.).\n\nBesides, it's pretty fun, if you like math.
1084746
The angle whose cosine is the cosine of y, has to be y.  The same with the angle whose sine is the sin x.  Thus, y+x=y+x, you cannot solve for y and x.
1006990
"The law of averages" is often used as a colloquial expression - as in "Well, I haven't had a best answer yet today, but I've answered 10 questions and by the law of averages I have to have one soon!"\n\nAnd in that context, it's not really meaningful.\n\nIn mathematics, on the other hand, there are 3 types of 'average' - mean, median and mode.\n\nMean is what everyone else here has been describing - sum all the numbers in a set and divide by the number of items in the set.\n\nMedian is the number in the middle - it's the number that has at most half the other numbers above it and at most half below it ("at most" because it might be one of the numbers itself)\n\nMode is the number with the most items equal to it.\n\nFor example - take a set of numbers 1,1,1,1,2,2,2,4,5,7.\n\nMean = 2.6 ((1+1+1+1+2+2+2+4+5+7)/10)\n\nMedian = 2 (1,1,1,1,2 below it; 2,4,5,7 above)\n\nMode = 1 (four one's, less of everything else)\n\nThey can all be useful - if you're told the average (mean) salary at a company is £20,000, for example, that doesn't sound too bad; but if 9 employees earn £10,000 and the boss earns £110,000, that's rubbish!  Either the median or the mode would give the game away here - they're both £10,000.
982220
Applications of trigonometry\nMarine sextants like this are used to measure the angle of the sun or stars with respect to the horizon. Using trigonometry and an accurate clock, the position of the ship can then be determined from several such measurements.\nEnlarge\nMarine sextants like this are used to measure the angle of the sun or stars with respect to the horizon. Using trigonometry and an accurate clock, the position of the ship can then be determined from several such measurements.\n\nThere are an enormous number of applications of trigonometry and trigonometric functions. For instance, the technique of triangulation is used in astronomy to measure the distance to nearby stars, in geography to measure distances between landmarks, and in satellite navigation systems. The sine and cosine functions are fundamental to the theory of periodic functions such as those that describe sound and light waves.\n\nFields which make use of trigonometry or trigonometric functions include astronomy (especially, for locating the apparent positions of celestial objects, in which spherical trigonometry is essential) and hence navigation (on the oceans, in aircraft, and in space), music theory, acoustics, optics, analysis of financial markets, electronics, probability theory, statistics, biology, medical imaging (CAT scans and ultrasound), pharmacy, chemistry, number theory (and hence cryptology), seismology, meteorology, oceanography, many physical sciences, land surveying and geodesy, architecture, phonetics, economics, electrical engineering, mechanical engineering, civil engineering, computer graphics, cartography, crystallography and game development.
736311
It equals (2/3)*pi.   It does not equal (-1/3)*pi  -- that would be (-inverse cosine (-1/2)).
129340
Have you ever heard of a slide rule?  Until computers came along, every mathematician used one to work out complex mathematical operations.  I don't think they even sell those things any more.
249103
well it depends on the angle between quantities. \nat 0 degree, simply add the given magnitude\nat 90 degree, use the pythagorean theorem\nat 180 degree, simply subtract the magnitude\nat any angle, other than 0, 90 and 180, use the laws of sine and cosine
358834
KNOW YOUR RELATED RATES FOR CALC!! thats one thing that killed me and know your 2-D rotation around a line intergrals.
728575
U should find out old class 9 Mathe. It can be helpful to u to understand easily basic of trigonometry i.e., 'Ө' and 'sine' in ur class standard.\nOld class 9 book can be available in old book shop. Find it at ur nearest old book shop.
728902
This can be done easily using a scientific calculator or there are many angular / decimal tables in Trig text books or many machinists handbooks or machinists guides.\n\nwww.industrialpress.com/en/tabid/63/Default.aspx
276671
(e^(cose^e+sin^e)/2)^pi\nhahaha ..just kidding
215627
well from what i learn we have a formulae for that right??!! then the formulae to find theta is.... to find cosine the formulae is adjecent over hypothenus in shortform its CAH or C=A/H. and to find sine is opposite over hypothenus or SOH or S=O/H.. and to fine tangent is opposite over adjecent or TOA or T=O/A.. so to remember it you just remmber it in the short form.. as if you have a chinesse friend name SOH CAH TOA.. soh for sine n cah for cosine n toa for tangent.. i hope thats what you want for the answer.. if not.. im sorry.. sooo sorryy..
228730
You can describe rotations and the effect they have on each point in the figure mathematically by means of simple trigonometric equations which can be condensed into a matrix. Imagine (or better, draw) a point on the plane in coordinate system X0,Y0, located at X0=1, Y0=0. Draw a line to the point from the origin. Now draw another coordinate system X1,Y1 with the same origin as X0,Y0 but rotated CW by an angle Theta. (Make Theta small, say 30 degrees.) What are the coordinates of our point in the new system? The answer is a function of Theta. We find that the point is above the X1 axis and nearer the Y1 axis. Specifically, X1 = X0*cosine(Theta) and Y1 = X0*sine(Theta). \nNow if you repeat this with a new point at X0=0, Y0=1, you find that X1 = -Y0*sine(Theta) and Y1 = Y0*cosine(Theta).\nNow the good part. You can put these four equations together to find X1,Y1 for any value of X0,Y0 (not just points located on one axis or the other). The result is\nX1=X0*cosine(Theta) - Y0*sine(Theta)\nY1=X0*sine(Theta) + Y0*cosine(Theta)\nNext you form a rotation matrix R from the Theta-dependent parts of these equations:\nR=[cosine(Theta)___ -sine(Theta)]\n__[sine(Theta) ___ cosine(Theta)] \nNow when you multiply any vector P0, representing any point in X0,Y0 coordinates, by this matrix R using the rules of matrix multiplication, you are actually using the above two equations, and the result is a vector P1 which is the same point represented in X1,Y1 coordinates. Expressed compactly, P1 = R*P0. P0 is said to be transformed by R to P1.\nOf course, this is a 2-dimensional transformation, and R is a 2-by-2 matrix. Sophisticated 3-D computer graphics use a 3-by-3 matrix implementing very similar equations to do 3-D transformations. This is how you can see convincing 3-D models of objects in rotation.
418030
Take a unit circle and a point p on the circle. Place the circle so that it is centered at the origin in a Cartesian xy-plane. The cosine of p, cos(p), is defined to be the x-coordinate, or abscissa, of p. The sine of p is the y-coordinate. These functions are the just the projection functions for the unit circle by the standard embedding in the Cartesian plane as described above.\nIt is common to give the points p on the 1-dimensional circle the coordinate referring to the arclength between p and the positive x-axis (as measured clockwise). Thus, the point (1, 0) on the unit circle is given the native coordinate (0), or 0 for short. Inversely, the point 0 in the unit circle has Cartesian coordinates (cos(0), sin(0)). Since the circumference of a circle is 2Pi, a point that is a quarter of the way around the circle from the positive x-axis is given the coordinate 2Pi/4 = Pi/2 and so forth. This system of coordinates is called radians and is the native way of measuring angles, as each angle corresponds to a unique point on the unit circle.\nThis relationship can be seen by drawing a radius from the origin to mark the angle from the positive x-axis and assigning that angle to the radian measure of wherever it intersects the unit circle. There are more analytical reasons as well, as you go on to study calculus.\nThe radius drawn above also gives the relationship between these circular projection functions, and the way one first encounters trigonometric functions, as ratios of the sides of right triangles. Now you should be able to visualize the triangles inside the unit circle (or any larger circle, dependent on the triangle's hypotenuse), and see why the trigonometric functions are cyclic in 2Pi, and derive some properties of the trigonometric functions that are not easily apparent from just looking at right triangles.\nIt is now however easy to see why all the basic trigonometric functions have a neighbor with prefix co-. The cosine is short for complementary sine. This is because the cosine of a point is obviously the same as the sine of the complementary angle.\nThe tangent function is so named because it is the length of a certain tangent to the circle; a tangent drawn from the positive x-axis to where it meets an extended radius of the circle. You may be able to work out the equation tan(p) = sin(p)/cos(p) from the geometry involved.\nThe arc trigonometric functions are so named because they measure arc length; they give you back the radian measure of the sine or cosine when you restrict these functions to one hemicircle (otherwise you get two possible answers).\nThe secant function does not give you an arclength; it is another function of points on the unit circle (and thus by our unit circle coordinate system, it is a function of arc length). In the right triangle formed by the tangent to the circle, the secant is the length of the hypotenuse. The arcsecant function returns the arc length on the unit circle that the secant intersects. See the sources below for illustrations.
1117196
use cosine law (because you don't know any of the angles) \n\n---- cosine law used when you know the measurement of an angle between 2 known sides or when there're no known angles at all\n\na^2= b^2 + c^2 - 2bc x cosA\n\nb^2= a^2 + c^2 - 2ac x cosB\n\nc^2= a^2 + b^2 - 2ab x cosC\n\nc is side opposite angle C, a the side opp angle A, b the side opp angle B.\n\nyou first have to draw the triangle\n\nafter drawing it, you will see that the side opp angle A is BC, and it is 7 units long (label the sides as a, b, or c if that helps you). what you do afterwards is put the values into the equation.\n\n(7)^2= (12)^2 +(10)^2 - 2(12)(10)cosA\n\nisolate the unknown value\n\n49 - 144 = 100 - 2(12)(10)cosA\n-95-100 = -2(12)(10)cosA\n-195 = -2(12)(10)cosA\n-195/(-2 x 12 x 10) = cosA\ncosA = 0.8125\n\nto find A, just press cos^-1 0.8125 on your calculator.\n\nangle A = cos^-1 0.8125\nangle A = 35.65908.... degrees\n\nrounded to nearest degree, angle A is 36 degrees\n\nhope that helped :)