find the exact value of cos 225 degrees .. cos(225)=cos(45+180) =cos45cos180+sin45sin180

The exact value of cos(225°) is -√(2) / 2. If we plug cos(225°) into our calculator, we will get an irrational number with approximate...

{eq}\displaystyle \cos 225 ^\circ {/eq} The Sixteen Special Angles and its Exact Values In a unit circle, the (3) three main trigonometric functions namely sine (sin), cosine (cos), and tangent (tan) correspond an exact value for each (16) sixteen special angles which are used to simplify a trigonometric expression without using a calculator.

cos 225 as function of a positve acute angle less than 45. The reference angel of cos 225 is -cos 45 but that is not less than 45 nor is it positve.-----The reference angle for 225 degrees is 225-180 or 45 degrees. But the cos 225 is negative. So you …

So, To take the cube (3rd) root (cube root) of z = 5[cos(225°+360°k) + j·sin(225°+360°k)] Take the cube root of the modulus 5, and divide the argument 225°+360°k by 3. Dividing 225°+360°k is 75²+120²k __ _ ∛z = ∛5 There are 3 unique different cube roots of a complex number, so we substitute 3 consecutive integeres for k and ...

De Moivre's theorem says that (cos x + isin x) n = cos nx + isin nx for any n that is a natural number. Does the same hold if n is rational? Perform the indicated operation. \\ \dfrac{6^{-1{(-5)^0} Find the standard form of the complex number, then represent the complex number graphically: \sqrt{8}(\cos 225^\circ + i\sin 225^\circ).

You can put this solution on YOUR website! Use the sum or difference identities to find the exact value of sin -165 degrees

cos(271)cos(61)+sin(271)sin(61)= cos(105)cos(225)&#872 Algebra -> Trigonometry-basics -> SOLUTION: Use an identity to find the exact value of each expression: Note: You are not allowed to use decimals in your answer.

Answer to: Evaluate the expression. sin^2 225 degree + cos^2 225 degree. By signing up, you'll get thousands of step-by-step solutions to your...

the functions for 225 degrees are the same as the functions for 45 degrees except that, since the angle is in quadrant 3, the rules for the signs of the functions in quadrant 3 apply and you get: sin(225) = -sqrt(2)/2