Connection between sine and cosine functions
If you compare the two graphs of the sine and cosine functions, you notice that the cosine wave is only a shifted sine wave. Generally speaking, this means:
$\cos(x)=\sin(x+\frac\pi2)$
$\sin(x)=\cos(x-\frac\pi2)$
$\sin(x)=\cos(x-\frac\pi2)$
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Hint
To make a sine or a cosine wave, you have to shift the function graphs with the value $c$.
- Cosine to sine function $c=+\frac\pi2$
- Sine to cosine function: $c=-\frac\pi2$