In a triangle with vertices A, B and C and sides a, b and c where a lower case side is opposite the upper case vertex,
a^2 = b^2 + c^2 - 2*b*c*Cos(A).
The second part of the question cannot be answered since "this type of question" is not described!
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.
The question asks about the "following". In such circumstances would it be too much to expect that you make sure that there is something that is following?
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.
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
Yes
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.
Yes, absolutely
true
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
The question asks about the "following". In such circumstances would it be too much to expect that you make sure that there is something that is following?
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.
Law of cosines
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
cosine = adjacent/hypotenuse
Yes
If it's a right triangle, use pythagorean's theorem (a2+b2=c2) to solve it. = If it's an oblique triangle, use the law of sines or cosines (see related link)
No, it applies to all triangles.