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How do you find the value of cos 50 degrees?

The cos of 50 degrees is 0.64279, the same as cos of 50 degrees in radians. To obtain 50 degrees in radian multiply 50° by / 180° = 5/18 . Cos 50degrees = cos (5/18 × .

How do you find cos 20 degrees?

The cos of 20 degrees is 0.93969, the same as cos of 20 degrees in radians. To obtain 20 degrees in radian multiply 20° by / 180° = 1/9 . Cos 20degrees = cos (1/9 × .

How do you find an angle with all sides?

To solve an SSS triangle:

  1. use The Law of Cosines first to calculate one of the angles.
  2. then use The Law of Cosines again to find another angle.
  3. and finally use angles of a triangle add to 180° to find the last angle.

What is the tan rule?

In a right triangle, the tangent of an angle is the length of the opposite side divided by the length of the adjacent side. In any right triangle, the tangent of an angle is the length of the opposite side (O) divided by the length of the adjacent side (A). In a formula, it is written simply as ‘tan’.

How do you know when to use law of sines or cosines?

The sine rule is used when we are given either a) two angles and one side, or b) two sides and a non-included angle. The cosine rule is used when we are given either a) three sides or b) two sides and the included angle.

How do you determine if the ambiguous case is given?

The Ambiguous Case of the Law of Sines

  1. See if you are given two sides and the angle not in between (SSA). This is the situation that may have 2 possible answers.
  2. Find the value of the unknown angle.
  3. Once you find the value of your angle, subtract it from 180° to find the possible second angle.
  4. Add the new angle to the original angle.

What are sines and cosines?

Sine and cosine — a.k.a., sin(θ) and cos(θ) — are functions revealing the shape of a right triangle. Looking out from a vertex with angle θ, sin(θ) is the ratio of the opposite side to the hypotenuse , while cos(θ) is the ratio of the adjacent side to the hypotenuse .

Is SSS law of cosines?

When you know the values for two or more sides of a triangle, you can use the law of cosines. In the following case, you know all three sides (which is called SSS, or side-side-side, in trigonometry) but none of the angles.

What do you need for law of cosines?

The Law of Cosines states: c2=a2+b2−2ab cosC . This resembles the Pythagorean Theorem except for the third term and if C is a right angle the third term equals 0 because the cosine of 90° is 0 and we get the Pythagorean Theorem.

Who discovered the law of cosines?

Jamshīd al-Kāshī