A fourth root is a number which multiplied by itself 4 times gives 0.0001.
Since it is an even root and the result is positive, the answer must include both negative and positive values. This is true since a negative times a negative is a positive.
Then we will multiply both sides of the equation by 2 π : x + π ( 1 - x ) = 0 x + π - π x = 0 x ( 1 - π ) = - π / · ( - 1 ) x ( π - 1 ) = π x = π / ( π - 1 )