Why do i get this error whenever i try to create a "sym"? "The second argument must be positive clear or real"

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new user 00 2018-6-12

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评论： new user 00 2018-6-12

sym qb h3; eqn = (da-db)/(da-db0) == (((qa-qb)*a3*h3/qb+vb0)/vb0)^(qa/(qa-qb)); solve(eqn,qb); In the eqn, except qb, all the numerical values were given.

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Steven Lord 2018-6-12

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You meant to use the syms function, not the sym function, to define your symbolic variables. The extra s is important.

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new user 00 2018-6-12

sorry that was a silly mistake i guess. now, i've got a new error. "explicit solutions cannot be found";

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