- #1
TheRedDevil18
- 408
- 1
Homework Statement
cos(-225)
The Attempt at a Solution
Would it become, -cos45 ?
Just want to make sure.
That's not right, it's 225 = 360 - 135.HallsofIvy said:225= 360- 35
Trigonometry is a branch of mathematics that deals with the relationships between the sides and angles of triangles. It is used to solve problems involving triangles, such as finding missing sides or angles.
In trigonometry, "reduce to" refers to simplifying a trigonometric expression or equation to its simplest form. This involves using trigonometric identities and basic algebraic operations to eliminate unnecessary terms or factors.
To reduce a trigonometric expression, you can use trigonometric identities such as the Pythagorean identity, double angle formulas, and sum and difference formulas. You can also use basic algebraic operations such as factoring, distributing, and combining like terms.
Some common trigonometric identities used for reducing expressions include the Pythagorean identities (sin^2x + cos^2x = 1 and tan^2x + 1 = sec^2x), double angle formulas (sin 2x = 2sinx cosx and cos 2x = cos^2x - sin^2x), and sum and difference formulas (sin(x ± y) = sinx cos y ± cosx sin y and cos(x ± y) = cosx cos y ∓ sinx sin y).
Reducing trigonometric expressions allows for easier manipulation and calculation of the values of trigonometric functions. It also helps in simplifying complex problems and making them more manageable. Additionally, reducing expressions can reveal relationships between different trigonometric functions and make them easier to understand.