To begin with, we remember that such concepts as "sinus", "cosine", and also there are still "Kothanns" and "Tangent" refer to such a section of mathematics as trigonometry. It is the ratio of the opposite of this corner of the category to the hypotenuse and is called a sine of acute angle. And the ratio adjacent to this corner of the category for hypotenuse - cosine.
How to find a cosine through a square root if the sinus is known
For all types of angles α, one designation is characterized:
sin. 2 α + Cos. 2 α = 1.
It connects the cosine and sinus of one corner. Provided that we are known for sinus, we can find the second value without problems - you need to remove the square root:
cos. α \u003d ± √1 - sin 2 α.
Pay special attention to a sign that should stand before the root sign. This can be determined by contacting the coordinate quarter. For sinus is a positive stay in 1 and 2 quarters, and for cosine - in 1 and 4.
How to find cosine through the formula of bringing if the sinus is known
It is such a formula plan that one can boldly call formulas.
Here f. means any trigonometric function, 
- Cofunction, which corresponds to it (sinus for cosine, cosine for sinus, etc.). A n -any integer. In front of the front, select the one that has an initial function for a coordinate quarter.
cOS ( π/ 2 - α) \u003d sin α.
Below is the sign of some formulas of the lifting.
Which of the above ways choose you - decide, of course, you. But more convenient, most often used, the first way is considered. It is he who is used in mathematics lessons. Easy to you achieve and good ratings.
0
884
