Context free language problem:

We have seen an unambiguous context-free grammar defining the expressions over the term a and using the operators +, * Its BNF definition is given below: E = T|E+T T = FT * F F = a Please modify the grammar to make (1) The precedence of + higher than *, and (2) The operator * right associative. (Please provide the BNF for the modified grammar.) (3) Please give the parse tree of the expression string a * a +a * a according to the modified grammar