Find the value of sinh(arccosh((sinh^2(pi/4) + cosh^2(pi/3))/tanh(2.5))), where sinh is the hyperbolic sine function, and arccosh is the inverse hyperbolic cosine function.
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Math question: Calculate the standard deviation of a data set: {5, 10, 15, 20, 25}, assuming it represents a sample. (
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What is the area of a regular pentagon with a side length of 8 cm?