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Question

Given:
S->…->xAy->…->w

if ____________, then A is useful, else useless symbol.

a.

A is a non terminal

b.

A is a terminal

c.

w Î L

d.

w Ë L

Answer: (c).w Î L

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Q. Given: S->…->xAy->…->w if ____________, then A is useful, else useless symbol.

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