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Mathematics 4 Online
OpenStudy (chunkymonkay):

can u please help me with irrational square roots!!!

OpenStudy (chunkymonkay):

OpenStudy (chunkymonkay):

@iGreen

OpenStudy (chunkymonkay):

@pooja195

OpenStudy (chunkymonkay):

@sammixboo

OpenStudy (chunkymonkay):

@Holly00d1248

OpenStudy (michele_laino):

here are your steps: \[\sqrt {134} = \sqrt {144 - 10} = \sqrt {144\left( {1 - \frac{{10}}{{144}}} \right)} = 12\sqrt {1 - \frac{{10}}{{144}}} \]

OpenStudy (michele_laino):

now we can use this approximation: \[\sqrt {1 - \frac{{10}}{{144}}} \cong 1 - \frac{{10}}{{288}}\]

OpenStudy (michele_laino):

so we can write: \[\sqrt {134} = 12\left( {1 - \frac{{10}}{{288}}} \right) = ...?\]

OpenStudy (chunkymonkay):

what do i do with the 10/288 divide?

OpenStudy (chunkymonkay):

@iambatman

OpenStudy (michele_laino):

because I used this approximation: \[\sqrt {1 - a} \cong 1 - \frac{a}{2}\] which is valid for all real numbers

OpenStudy (chunkymonkay):

ok but i dont understand what do i do multiply,divide or what?

OpenStudy (michele_laino):

I have started from 134= 144-10

OpenStudy (michele_laino):

that is a simple numeric identity

OpenStudy (michele_laino):

is it ok?

OpenStudy (chunkymonkay):

im sorry im confused i know 144-10 is 134 but what do i do?

OpenStudy (michele_laino):

we did it in order to apply the approximation that I wrote before

OpenStudy (chunkymonkay):

im confused i dont know what to write with all those numbers

OpenStudy (chunkymonkay):

soo its 1-a/2

OpenStudy (michele_laino):

yes! it is only a formula which we can apply to our computation when we need of it: \[\sqrt {1 - a} \cong 1 - \frac{a}{2}\]

OpenStudy (michele_laino):

it is valid for those values of "a" such that a<1

OpenStudy (michele_laino):

and the quantity 10/144 is less than 1

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