Can I get $\cos(x)/\!\cos(y)$ if I have $\sin(x)/\!\sin(y)$?
12841
Ratio of sines given, find ratio of cosines?
106867
Limit of $\cos(x)/x$ as $x$ approaches $0$
148207
Express $\cos 6\theta $ in terms of $\cos \theta$
82586
Why is cos -x equal to cos x?
13297
Prove the following trigonometric identity without a calculator involved
29370
Trig integral $\int ( \cos{x} + \sin{x}\cos{x}) \, dx $
148624
Replacing Tan[x] with Sin[x]/Cos[x]
14410
If $(1+ \cos A) (1+ \cos B) (1+\cos C)= y = (1- \cos A) (1-\cos B) (1-\cos C)$ then $y = \pm \sin A \sin B \sin C$
11744
Maximum and minimum of $f(x)=\cos(\sin(x))-\sin(\cos(x))$
617
Find θ: $β=\arctan\frac{(R+r)·\sin(θ)-r·\sin(θ(1+\frac{R}{r}))}{(R+r)·\cos(θ)-r·\cos(θ(1+\frac{R}{r}))}$
96388
Prove $\sin(x)\tan(x) > x^2$ for $x \in ( \,0, \frac{\pi}{2}) \,$
87934
Deducing $\sin x + \cos x \ge 1$ from $(\sin x + \cos x)^2 = 1 + 2 \sin x \cos x$
106803
How to see $\cos x \leq \exp(-x^2/2)$ on $x \in [0,\pi/2]$?
122145
Evaluating Limit - $(1-(\cos x)^{\sin x})/(x^3)$
6465
How to prove periodicity of $\sin(x)$ or $\cos(x)$ starting from the Taylor series expansion?
5747
$\cos(\arcsin(x)) = \sqrt{1 - x^2}$. How?
143072
Proving $|\sin x - \sin y| < |x - y|$