Using Differentials (not partial derivatives) to prove that d𝜃/dx = -sin(𝜃)/r
108808
$x =r\cos \theta$ and $y = r\sin\theta$, determine $\frac{\partial r}{\partial x}$ and $\frac{\partial \theta}{\partial x}$
124208
Proof $|\sin(x) - x| \le \frac{1}{3.2}|x|^3$
69020
Complex analysis : If $z =re^{i\theta}$, then prove that $|e^{iz}| =e^{-r\sin\theta}$
75888
How to prove the function $y = \sin x$ is not a closed function?
139631
How to take this exterior derivative of the expression $du - \sum_i p_i dx_i$?
100283
How to understand the notion of a differential of a function
33396
Generalizing a Trig Identity
150734
Solving $\lim\limits_{x\to0} \frac{x - \sin(x)}{x^2}$ without L'Hospital's Rule.
30030
An integration question to be solved without using differentiation under the integral sign.
153158
how to get $dx\; dy=r\;dr\;d\theta$
128795
$n$th derivative of $e^x \sin x$
33628
Prove that $\sin(\sqrt x)$ not periodic
137844
Proof of $\sin nx=2^{n-1}\prod_{k=0}^{n-1} \sin\left( x + \frac{k\pi}{n} \right)$
77810
Solving Trigonometric Derivatives
85944
Prove $ \sin x + \frac{ \sin3x }{3} + ... + \frac{ \sin((2n-1)x) }{2n-1} >0 $
16253
Proof that $|\sin(nx)| \le n|\sin(x)|$
15287
Proving that second derivative is perpendicular to curve