Is $ \sinh(x) \sinh(y)=\sinh(y) \sinh(x)$? While evaluation a question on multiple integral I have got answer $4\sinh(3) \sinh(1)$.
It was a multiple choice questions with
a) $4\sinh(3) \sinh(1)$
I think both a and b option are correct since $\sinh(1)$ ,$\sinh(3)$ is multiplication of numbers it should commute but in answer option a is mention .
Am I correct both option is correct ? If wrong please explain why ?