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When you have a right angle what does the law of cosines reduce to?
Wiki User
∙ 12y ago
cosine = adjacent/hypotenuse
Wiki User
∙ 12y ago
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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.
What is the law of cosines?
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 CC = included anglec = side opposite angle C (c)a = side ab = side bThe 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)
When do you use law of sine?
There are several cases when you would want to use the law of sines. When you have angle angle side, angle side angle, or angle side side you would use the law of sines.
Find the length of the side opposite angle a?
It depends on what else you know. If it is a non-right triangle, and you only know angle a, it is impossible to fing side A (the side opposite an angle usually has the same letter, but capitalized). If you know the other two sides, then I would use the law of cosines: For a triangle with sides A B C A = √(B2+C2-(2*B*C*(cos (a)))) If you know another angle and one side, I would use the law sines: A/(sin a) = B/(sin b) therefore, A = (sin a) * B/(sin b) If it is a right triangle, and you know another side, than your job is even easier: If you know the hypotenuse (side C), than: A = C *(sin a) If you know the adjacent side (side B), than: A = B * (tan a)
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 does the law of cosines reduce to when dealing with a right triangle?
D. The Pythagorean Theorem
How do you find a missing side of a triangle without a right angle?
Having sufficient angles or sides one can use either, The Law of Sines, or, The Law of Cosines. Google them.
Can the law of cosines be applied to right and non-right triangles?
Yes
When do you use the Law of Cosines?
We use the law of Cosines to be able to find : 1. The measure of the third side, when the measure of two sides and the included angle of a triangle ABC are known. 2. The measure of any angle, when the measure of the three sides of a triangle ABC are known.
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.
Is it true that the law of cosines reduces the Pythagorean theorem with right triangles?
Yes
Can you use the Law of Cosines to solve a triangle when you are given two side lengths and the included angle measure?
Yes, absolutely
What type of triangle has angle A 37 degree angle B 56 degree angle C 87 degree?
Acute triangle - all of the angles are less than a right angle (90°).Scalene triangle - none of the sides or angles are congruent. It can be shown that if no two angles are the same, then no two sides are the same using the Law of Sines and Law of Cosines.
How do you find the unknown angle of a triangle?
If you have two other angles, then add up those 2 and subtract that from 180. if you have all 3 sides then use the law of cosines: a squared = b squared + c squared - 2bc (cos A) If you have one angle and the 2 included sides, use the law of cosines as well. if you have an angle and the length of its opposite side, and the side opposite to the angle you want, then use the law of sines: sin A/ a = sin B/ b if you have the angle and the length of its opposite side and another angle, use the law of sines to figure out the unwanted angle anyway and then follow situation 1.
When do you use law of sines and law of cos sines?
Use Law of Sines if you know:Two angle measures and any side length orTwo side lengths and a non-included angle measure.Use Law of Cosines if you know:Two side lengths and the included angle measure orThree side lengths.
Is this statement true or falseYou can use the Law of Cosines to solve a triangle when you are given the lengths of the three sides and no angle measures?
true
