Answer:
Changes made to your input should not affect the solution:
(1): "f3" was replaced by "f^3".
Unauthorized use of the imaginary unit "i" or syntax error in complex arithmetic expression
.... V
find^2sqrtof312.5
The symbol "i" is only allowed in complex arithmetic, for example:
(3/5+7i)+(0.3-7.002i)
(5+77i)-(19/4-8i)
(240-22i)*(247/7+2.222i)
(33/5+99i)/(33/5-88i)