Only 5% Can Solve - A nice Math Olympiad trigonometric Problem | Find Value of Sinx and X

[@sy8146]

Thank you for explaining. From sinx=±1/(√2) , x = ±π/4 (= ± 3.14・・・/4 = ± 0.785・・・ ).

[@Rando2101]

Here is what I think:
Using AM-GM inequality:
9^sin²(x)+9^cos²(x)
>=2sqrt(9)=6
Which means the equality happens when sin(x)=cos(x)
You can continue from there to get the solution

[@robdavies2483]

Doesn't X = PI/4 OR 0.78...