Writing approximation symbol(≈) in LaTeX

Approximation symbol

$\approx$
\approx

$\thickapprox$
\thickapprox

Let’s see some examples with approximation symbol

Approximations between metric and imperial units

$8km\approx 5miles$
8km\approx 5miles

$1m \approx 40\thinspace inches$
1m \approx 40\thinspace inches

$\Pi \approx 3.14$
\Pi \approx 3.14

$30cm \approx 1foot$
30cm \approx 1foot

$2.5cm\approx 1\thinspace inch$
2.5cm\approx 1\thinspace inch

$1kg\approx 2.2 \thinspace lbs$
1kg\approx 2.2 \thinspace lbs

$1 litre\approx 1{3 \over4}\thinspace pints$
1 litre\approx 1{3 \over4}\thinspace pints

$1gallon \approx 4{1 \over2}\thinspace litres$
1gallon \approx 4{1 \over2}\thinspace litres

$1\thinspace acre \approx {2 \over5}\thinspace hectare$
1\thinspace acre \approx {2 \over5}\thinspace hectare

$450g \approx 1 b$
450g \approx 1 b

Basic linear approximations

$\displaystyle \frac{1}{x-1} \approx 1+x,\qquad for \thinspace x \approx 0$
\displaystyle \frac{1}{x-1} \approx 1+x,\qquad $for$ \thinspace x \approx 0

$(1+x)^r \approx 1+rx , \qquad for \thinspace x \approx 0;\qquad$ r is any real number
(1+x)^r \approx 1+rx ,\qquad for \thinspace x \approx 0; \qquad r is any real number

$sin \thinspace x\approx x ,\qquad for \thinspace x \approx 0;$
sin \thinspace x\approx x , \qquad for \thinspace x \approx 0;

Basic quadratic approximations

$\displaystyle \frac{1}{x-1} \approx 1+x+x^2,\qquad for \thinspace x \approx 0$
\displaystyle \frac{1}{x-1} \approx 1+x+x^2,\qquad for \thinspace x \approx 0

$(1+x)^r \approx 1+rx + \frac{r(r-1)}{2} x^2, \qquad for\thinspace x \approx 0; \qquad$ r is any real number
(1+x)^r \approx 1+rx + \frac{r(r-1)}{2} x^2, \qquad for\thinspace x \approx 0; \qquad r is any real number

$cos x \thinspace 1-\displaystyle \frac{x^2}{2}\approx x ,\qquad for\thinspace x \approx 0;$
cos x \thinspace 1-\displaystyle \frac{x^2}{2}\approx x ,\qquad for\thinspace x \approx 0;