#2**+2 **

4.4721359549995794 - 2√5 \(\stackrel{?}{=}\) 0

2*√5 is the same as √20 so we can say...

4.4721359549995794 - √20 \(\stackrel{?}{=}\) 0

Add √20 to both sides.

4.4721359549995794 \(\stackrel{?}{=}\) √20

Square both sides.

(4.4721359549995794)^2 \(\stackrel{?}{=}\) 20

20.00000000000000006423465417690436 \(\stackrel{?}{=}\) 20

So we can see that it is very close, but not quite completely true.

Here is how I got the result on the last step.

Also, since √20 is a non-terminating decimal, there is no way that a terminating decimal can be equal to it.

hectictar
Jun 20, 2017

#2**+2 **

Best Answer

4.4721359549995794 - 2√5 \(\stackrel{?}{=}\) 0

2*√5 is the same as √20 so we can say...

4.4721359549995794 - √20 \(\stackrel{?}{=}\) 0

Add √20 to both sides.

4.4721359549995794 \(\stackrel{?}{=}\) √20

Square both sides.

(4.4721359549995794)^2 \(\stackrel{?}{=}\) 20

20.00000000000000006423465417690436 \(\stackrel{?}{=}\) 20

So we can see that it is very close, but not quite completely true.

Here is how I got the result on the last step.

Also, since √20 is a non-terminating decimal, there is no way that a terminating decimal can be equal to it.

hectictar
Jun 20, 2017