问题描述:

This code is non-sensical so getting the result isn't the important part, understanding why the two methods arrive at different conclusions is what I'm trying to understand.

# data

days <- c(528, 900, 1050, 1300)

returns <- c(-46.9363726590971, 113.096047917561, -55.1435291957069, 251.540399180745)

# the operation I would like to do; note the NaN for two of them

returns ^ (252 / days)

# pulling out the first values fails in the same way

(returns[1]) ^ (252 / days[1])

# and sapply yields the same result

sapply(X = seq_along(days), FUN = function(i) returns[i] ^ (252 / days[i]))

# just using the numbers gives a different result for the negative numbers

-46.9363726590971 ^ (252 / 528)

113.096047917561 ^ (252/900)

-55.1435291957069 ^ (252/1050)

251.540399180745 ^ (252/1300)

Why is this the case?

Thank you

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