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$\begingroup$

(Note: The ? is where I have to fill in something)

Prove:

$$ \begin{align} \sinh2x & = 2\sinh x\cosh x\\ \sinh2x & = \sinh (x + ?)\\ & = \sinh x(?) + \cosh x \sinh x\\ & =\space?\\ \end{align} $$

I know that there is a way of proving it by using the basic definitions of $\cosh$ and $\sinh$, but that is not what the question is asking.

  • 0
    Hint: $2x=x+x$.2012-10-28
  • 0
    where did the hyperbolic cosign go?2012-10-28

1 Answers 1