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Required Information

Consider a positively cambered alfoil with a zero$-$lift angle of $\backslash (-4\mathrm{.}000^\{\backslash$circ$\}\backslash ).$ The lift slope is $0\mathrm{.}1$ per degree.

At what angle of attack must the upside$-$down airfoll be set to generate the same lift as that when it is right$-$side$-$up at a $\backslash (5^\{\backslash$circ$\}\backslash )$ angle of attack?

The angle is