Cos Inverse is also written as Arccos and Cos-1 and is called an anti trigonometric function. The cos inverse is an inverse trigonometric function with restricted domains.
The Cos inverse Formula is :
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Cos x = Adjacent / Hypotenuse |
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Cos-1 (Adjacent/Hypotenuse) = x |
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Cos-1 (-x) = Π– Cos-1x Cos-1 x = Π– Sin-1 ( Cos-1 x = Sin-1 |
Arc cos Questions
Cos inverse formula is one amongst the other six inverse trigonometric functions.
Question: Find the exact Value of Arccos(-½)
Solution:
arccos(- 1 / 2)
Assume y = arccos(- 1 / 2).
cos y = – 1 / 2 with 0 ≤ y ≤ Π(Cos Theorem) … (1)
Cos (Ï€ / 3) = 1 / 2 (Use table of Special Angles)
And also, cos(Π– x) = – cos x.
cos (π – π/3) = – 1 / 2 …(2)
Compare statement 1 with statement 1
y = Π– Π/ 3 = 2 Π/3
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