I have no idea how to approach this problem.
Guess the value of the limit if it exists by evaluating the function at the given number. Let F(x)=tan(8x)-tan(2x)-6x/x^3
Values given for x are
0.2, 0.1, 0.05, 0.01, 0.001, 0.0001
put each of thosee vaues of x in, one by one.
tan (8*.2) - tan(2*.2) - 6*.2/.2^3
then tan (8*.1) - tan (2*.1) etc etc etc
hopefully as you work don the list your answers will get close and closer to
tan (8 * 0.0 .....
which is f(0)
now what should that be anyway?
f(0) = tan (8*0) - tan (2*0) - 6/ 0^2 = 0 - 0 - 6/0
well that 6/0^2 is kind of tricky :)