Step-by-step explanation:
F(x) is the antiderivative (or integral) of f(x).
F(x) = ∫ f(x) dx
F(x) = sin(1/(x² + 1))
∫₁² f(x) dx
= F(2) − F(1)
= sin(1/(2² + 1)) − sin(1/(1² + 1))
= sin(⅕) − sin(½)
= -0.281
