Podcast #128: We chat with Kent C Dodds about why he loves React and discuss what life was like in the dark days before Git. Listen now.

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# Jelly, 9 bytes

÷400⁵*÷S$ The input is an array [Ra, Rb] and the output is an array [Ea, Eb]. ## Explanation ÷400⁵*÷S$  Input: array [Ra, Rb]
÷400       Divide each by 400, makes [Ra/400, Rb/400]
⁵*     Raise 10 to that power, makes [10^(Ra/400), 10^(Rb/400)]
$Monadic chain operating on previous result ÷ Divide each by S The sum of the whole Makes [10^(Ra/400)/(10^(Ra/400) + 10^(Rb/400)), 10^(Rb/400)/(10^(Ra/400) + 10^(Rb/400))] = [1/(1 + 10^((Rb-Ra)/400)), 1/(1 + 10^((Ra-Rb)/400))]  # Jelly, 9 bytes ÷400⁵*÷S$


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# Jelly, 9 bytes

÷400⁵*÷S$ The input is an array [Ra, Rb] and the output is an array [Ea, Eb]. ## Explanation ÷400⁵*÷S$  Input: array [Ra, Rb]
÷400       Divide each by 400, makes [Ra/400, Rb/400]
⁵*     Raise 10 to that power, makes [10^(Ra/400), 10^(Rb/400)]
$Monadic chain operating on previous result ÷ Divide each by S The sum of the whole Makes [10^(Ra/400)/(10^(Ra/400) + 10^(Rb/400)), 10^(Rb/400)/(10^(Ra/400) + 10^(Rb/400))] = [1/(1 + 10^((Rb-Ra)/400)), 1/(1 + 10^((Ra-Rb)/400))]  1 # Jelly, 9 bytes ÷400⁵*÷S$


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