38. Is the following argument correct? (x + 3)(x - 3) lim lim lim (x - 3) - -61.\f5.81. Special Theory of Relativity According (o the special theory of relativity, when force and velocity are both along a straight line. resulting in straight-line motion, the magnitude of the acceleration of a particle acted upon by the force is : A\\ e where v is its speed, F is the magnitude of the force, m is the mass of the particle at rest, and is the speed of light, a. Find the domain of f, and use this result to explain why we may consider only lim,_,.- fie). b. Find lim,,. f{r), and interpret your result. 83. Use the Squeeze Theorem to find lim, y x sin(1/x). Verify your result visually by plotting the graphs off(@) = =X, g(x) = x sin(1/x), and h(x) = x in the same window.84. Use the Squeeze Theorem to find lim,, Vx cos(1/x ) Verify your result visually. Hint: See Exercise 83