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Value of Cos 120 degree can be calculated using other trigonometric angles 90 degrees and 180 degrees. These cosine values can be gained from the trigonometric table.
The value of cos 120 degrees is -0.5. Cos 120 degrees in radians is written as cos (120° × π/180°), i.e., cos (2π/3) or cos (2.094395. . .). In this article, we will discuss the methods to find the value of cos 120 degrees with examples.
Solution. Find the value of cos 120 °. We know that. cos α + β = cos α cos β - sin α sin β. Now by substituting the value of α = 90 ° and β = 30 ° in the trigonometric identity we get. cos 90 ° + 30 ° = cos 90 ° cos 30 ° - sin 90 ° sin 30 ° ⇒ cos 90 ° + 30 ° = 0 - 1 × 1 2 ∵ cos 90 ° = 0, sin 90 ° = 1 and sin 30 ° = 1 2 ⇒ cos 120 ° = - 1 2.
3 days ago · Cos 120 degree is equal to minus half which can be written as (- ½ ) or (-0.5). Cos is one of the functions of Trigonometry that deals with the relationship between the angles and sides of a right-angled triangle. So in short, we can say that measuring a triangle (specifically right-angled triangle) is trigonometry.
4 days ago · Example: how to use a cosine calculator. This cosine calculator is a twin tool to our sine calculator – add to them the tangent calculator, and you'll have a pack of the most popular trigonometric functions. Simply type the angle – in degrees or radians – and you'll find the cosine value instantly.
Exact Form: −1 2 - 1 2. Decimal Form: −0.5 - 0.5. Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.
