# Many approximations!

Level pending

Given that $$secx + tanx \approx 1 - ln(1-x)$$, and that $$secx + tanx = \frac{3}{2}$$, the approximate value for the principle value of $$sin^{-1}\frac{5}{13}$$ can be expressed as $$sin^{-1}\frac{5}{13} \approx A + Be^C$$, find the value of $$-10(A+B+C)$$.

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