Apr 27, 2016 · Opposite real number identities(why $\cos(-x)=\cos x$) 6 Given three chords on a circle which form an interior triangle what is the area of the triangle formed?

Apr 17, 2017 · The equation in question is a transcendental equation.Apart of guessing, numerical or analytical methods, there is no way of solving the equation without using another transcendental function, and therefore argue in circles.

In quadrant IV, $\cos{x}$ is positive, so taking a square root gives us $$\cos{x} = \sqrt{1 - \sin^2{x}}$$

Aug 19, 2018 · The sequence of $$ a_x ={\cos (x)\over x} $$ does converge to zero. As a result, intuitively $$ \sum_{x=1}^\infty {\cos (x)\over x} $$ should also converge right?

Apr 13, 2012 · There was a proof that $\cos^{(3)}\sinh x=\sin^{(3)}\cosh x$ has infinitely many solutions in a previous version of this answer, but it turns out this is irrelevant to the question.

The maximum value of cos(x+y)=1. The maximum values of cos(x) and cos(y) are 1. Since cos(x)+cos(y)=2cos(x+y) for some values of x and y, it cannot be the case that cos(x)+cos(y)=cos(x+y) except for special values of x and y.

Feb 18, 2020 · It says that the fixed point for $\cos x=x$ using Intermediate Value Theorem.But I couldn't get how they computed the fixed point for $\cos x$.Do anyone know how they computed this? fixed-point-theorems

Sep 21, 2020 · $$\cos(5x) + i\sin(5x) = (\cos(x) + i\sin(x))^5$$ and using the binomial theorem I think the answer is the real part of the expansion but I fail to see it. The answer is $16x^5-20x^3+5x$ .

Dec 28, 2015 · Sometimes it can be useful to use this identity: $\cos(x) \cos(y) = \frac{1}{2} \left[ \cos(x+y) + \cos(x-y)\right]$ Usually you can change trigonometric function multiplication to sum or backwards. Multiplication of any two functions with different variables cannot be simplified into one function of one variable.

Apr 13, 2018 · Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.