I'd love to know if anyone has a good mnemonic for answers of the following:
$$\frac{\mathrm{d}}{\mathrm{d}x} \, \sin x$$
$$\frac{\mathrm{d}}{\mathrm{d}x} \, \cos x$$
$$\int \sin x \,\mathrm{d}x$$
$$\int \cos x \,\mathrm{d}x$$
I know the first one by heart, and derive the others from it. This sometimes takes me up to five seconds, longer if I'm not really thinking clearly! Does anyone have a good mnemonic for the answers to these common occurrences?
In the trigonometric unit circle. Differentiation is clockwise and integration is anticlockwise. For example if you were to search for the derivative on $\sin(x)$ then clockwise next is the derivative which is $\cos(x)$. Similarly, the antiderivative of $-\sin(x)$ is found by going anticlockwise on the unit circle, and we get $\cos(x)$.
source: https://getrevising.co.uk/https_proxy/1364