Simple tabulations for each function can be done with WolframAlpha: see.
They can also be done with pocket calculator: see.
• At the beginning F(x) = sin(x)/x is calculated.
function F(x) { with(Math) { y = sin(x)/x return y }}
For example, I can deduce that, as x → 0, sin(x)/x → 1:
and that, as x → ∞, sin(x)/x → 0:
• (tan(x)-sin(x)+1-cos(x)) / (x*x+1-cos(x)) as x → 0
function F(x) { with(Math) { y = (tan(x)-sin(x)+1-cos(x)) / (x*x+1-cos(x)) return y }}
The limit is 1/3.
• √(x*x+x)-√(x*x-2) as x → ∞
function F(n) { with(Math) { y = sqrt(x*x+x)-sqrt(x*x-2) return y }}
The limit is 1/2.
• n / (n!)1/n as n → ∞
function F(x) { with(Math) { y = x / pow(Fat(x), 1/x) return y }} function Fat(n) { with(Math) { y = 1; for (k=1; k <= n; k++) {y = y*k} return y }}
[170, 171, 172, 173, 174, 175 ->] 2.663087878748024, 0, 0, 0, 0, 0 -------- [150, 160, 170, 180, 190 ->] 2.6569209686814057, 2.660179125103347, 2.663087878748024, 0, 0 -------- [1, 50, 100, 150, 200 ->] 1, 2.5663063992029507, 2.6320853228463696, 2.6569209686814057, 0
171 → 0 because (for computer) 171! = infinity (170! = 7.257415615307994e+306). F(170) = 2.663087878748024. It can be proven that (as N → ∞) F(N) → e = 2.71828182...
• F(x) = sin(x)−tan(x) as x → 0. Limit is 0. With which order F(x) tends to 0?
function F(n) { with(Math) { y = sin(x)-tan(x) return y }}
[1e-1, 1e-2, 1e-3, 1e-4, 1e-5 -> ] -0.0005012554386223944, -5.00012500542768e-7, -5.000001250705932e-10, -4.999999980020986e-13, -5.000001606324245e-16
If x is divided by 10, F(x) is divided by 1000. F(x) is an infinitesimal of order 3.
sin(x)-tan(x) ≈ Q·x3. Q = ?
I study the limit of (sin(x)-tan(x))/x³:
function F(x) { with(Math) { y = (sin(x)-tan(x))/pow(x,3) return y }}
[1e-1, 1e-2, 1e-3, 1e-4, 1e-5 ->]
-0.5012554386223943, -0.5000125005427679, -0.5000001250705932, -0.4999999980020986, -0.5000001606324244
I can deduce that Q = −1/2, that is, that (as x → 0) sin(x)-tan(x) ≈ −1/2·x3.
• F(x) = log(1+x2)/(sin(xk). How much is the limit for x which tends to 0 when k changes?
function F(x) { with(Math) { k = 2 y = log(1+x*x)/sin(pow(x,k)) return y }}
[k = 4: 1e-2, 1e-3, 1e-4, -1e-2, -1e-3, -1e-4 ->]
9999.500033329732, 999999.4999180668, 99999998.8922529, 9999.500033329732, 999999.4999180668, 99999998.8922529
--------
[k = 3: 1e-2, 1e-3, 1e-4, -1e-2, -1e-3, -1e-4 ->]
99.99500033331397, 999.9994999180667, 9999.999889225292, -99.99500033331397, -999.9994999180667, -9999.999889225292
[k = 0: 1e-2, 1e-3, 1e-4, -1e-2, -1e-3, -1e-4 ->]
0.00011883356899837213, 0.0000011883945114831993, 1.1883950926137091e-8, 0.00011883356899837213, 0.0000011883945114831993, 1.1883950926137091e-8
--------
[k = 1: 1e-2, 1e-3, 1e-4, -1e-2, -1e-3, -1e-4 ->]
0.00999966669360799, 0.0009999996665846695, 0.00009999999905891957, -0.00999966669360799, -0.0009999996665846695, -0.00009999999905891957
--------
[k = 2: 1e-2, 1e-3, 1e-4, -1e-2, -1e-3, -1e-4 ->]
0.9999500049995564, 0.9999994999182334, 0.9999999889225291, 0.9999500049995564, 0.9999994999182334, 0.9999999889225291
k = 2, F(x) → 1. k = 1, F(x) → 0. k = 0, F(x) → 0.
k = 3, 5, ...; if x → 0+, F(x) → ∞; if x → 0-, F(x) → −∞.
k = 4, 6, ..., F(x) → ∞.