>>823
asinxをArcsinxの意と解釈して
x=sin(asin(1/3)+asin(7/9))
=sin(asin(1/3))cos(asin(7/9))+cos(asin(1/3))sin(asin(7/9))
=(1/3)(4√2/9)+(7/9)(2√2/3)
PSPくれ。