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It is a mathematical equation that allows you to "solve" a triangle (find all length and angle values), if you know 2 sides and an included angle, or all three sides. It doesn't have to be a right triangle. You can find the cosine on a calculator easily.
c2 = a2 + b2- 2ab cos C
C = included angle
c = side opposite angle C (c)
a = side a
b = side b
The cosine law relates the length of the sides of a triangle to one of the angles in the triangle. If the triangle is labelled with vertices A, B, C with usual notation for edges (ie a is the side opposite the vertex A, so not touching A) and if x is the angle at vertex C then the cosine law says (c^2)=(a^2)+(b^2)-2abcos(x)
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When you have a right angle what does the law of cosines reduce to?
cosine = adjacent/hypotenuse
What are the formulas for law of sines and law of cosines?
sine: sin(A) sin(B) sin(C) cosines: a2=b2+c2-2bc cos(A).........----- = ----- = ------........,,,.a .......b........ ca is side BC A is angle A sin(A) means sine of angle Apsst, theres a law of tangents too, but its so complicated that im not gonna post it hereLaw of sine -A B C------ = ------ = ------Sin(a) Sin(b) Sin(c)
Topics need for trigonometry?
There are several topics under the broad category of trigonometry. * Angle measurements * Properties of angles and circles * Basic trigonometric functions and their reciprocals and co-functions * Graphs of trigonometric functions * Trigonometric identities * Angle addition and subtraction formulas for trigonometric functions * Double and half angle formulas for trigonometric functions * Law of sines and law of cosines * Polar and polar imaginary coordinates.
Sine and cosine of real numbers?
Putting a question mark at the end of a phrase does not make it a sensible of even an answerable question. Sine and cosine of real numbers? Yes, they do exist. In fact, sines and cosines of complex numbers also exist. Does that answer the question?
How do you simplify cot of theta times sin of theta?
By converting everything to sines and cosines. Since tan x = sin x / cos x, in the cotangent, which is the reciprocal of the tangent: cot x = cos x / sin x. You can replace any other variable (like thetha) for the angle.
Who discovered the law of cosines?
A caveman from 10,000 BCal-Kashi was the 1st to provide an explicit statement of the law of cosines in a form suitable for triangulation
When would you use the law of sines or law of cosines instead of a trigonometric ratio?
Trigonometric ratios, by themselves, can only be used for right angled triangles. The law of cosines or the sine law can be used for any triangle.
How do you calculate the angles of a triangle knowing the sides?
Law of cosines
Law of cosines with a right angle?
The law of cosines with a right angle is just the pythagorean theorem. The cosine of 90 degrees is 0. That is why the hypotenuse squared is equal to the sum of both of the legs squared
What are the answers to law of cosines in A plus?
The law of cosines can be written in one form as: c2 = a2 + b2 - 2abCos C. Without 3 of the 4 variables being given, there is no way to answer this question.
When you have a right angle what does the law of cosines reduce to?
cosine = adjacent/hypotenuse
Can the law of cosines be applied to right and non-right triangles?
Yes
Can The law of cosines can only be applied to acute triangles?
No, it applies to all triangles.
What does the law of cosines reduce to when dealing with a right triangle?
D. The Pythagorean Theorem
Is it true that the law of cosines reduces the Pythagorean theorem with right triangles?
Yes
Can law of cosines can only be applied to acute triangles?
No, it applies to all triangles.
How are all three versions of the law of cosines correct?
It follows from the cyclical symmetry of the cosine rule.
