Consider the functional \(J(y)=\int_a^b F\left(x, y, y^{\prime}\right) d x\) where F(x, y, y') = y' + y for admissible functions y. Then J has
1
no extremals
2
several extremals
3
y(x) = e-x as an extremal
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y(x) = constant as an extremal
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