# What is a haitch?

Calculus Level 1

$\large{\begin{array} {l c l } \frac{d}{dx} \sin x &= &\cos x \\ \frac{d}{dx} \cos x &= &\sin x \\ \frac{d}{dx} \sinh x &= &\cosh x \\ \frac{d}{dx} \cosh x &= &\sinh x \end{array}}$

One of the above equations is wrong, which one?

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