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How do you find the rationalising factor of root2 + root7  root10?
 one year ago
 one year ago
How do you find the rationalising factor of root2 + root7  root10?
 one year ago
 one year ago

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pratu043Best ResponseYou've already chosen the best response.0
dw:1344951900463:dw
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
multiply that by its conjugate @pratu043 what do you get?
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
By conjugate you mean: dw:1344952032255:dw
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
\[\large{(\sqrt{2}+\sqrt{7}\sqrt{10})(\sqrt{2}+\sqrt{7}+\sqrt{10})=?}\]
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
dw:1344952080072:dw
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
@pratu043 what do you get by multiplying that.. ?
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
How do you find the conjugate?
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
I only know how to find for binomial surds.
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
@pratu043 let the expression given be like this: \[\large{(\sqrt{2}+\sqrt{7})(\sqrt{10})}\]
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
I meant to say that: a+bc = (a+b)(c) right?
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
dw:1344952309566:dw
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
dw:1344952351465:dw What do you do with  root10?
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
dw:1344952415376:dw sorry
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
ok leave that for once... what will be the conjugate of a+b ?
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
right so let a = c+d and b = b now can u tell me what will be the new conjugate? : (c+d)+(b) conjugate = ?
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
right so what will be the conjugate of : \[\large{(\sqrt{2}+\sqrt{7})(\sqrt{10})}\]
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
dw:1344952630671:dw ok, I got the conjugate part.
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
right now : multiply this conjugate with original expression
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
dw:1344952686106:dw right?
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
good so we have: \[\large{2\sqrt{14}1}\] now:(√2 + √7  √10)[(√2 + √7 + √10) (2√14 + 1)] do this
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
dw:1344952926110:dw
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
But why should we do this?
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
it is a step towards the answer
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
also try to check that out pratu that u did: can that be more simplified?
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
@pratu043 you there?
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
sorry yes i am there.
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
do you mean that we should try and convert the irrationals in that expression to mixed surds?
 one year ago

pratu043Best ResponseYou've already chosen the best response.0
I think I can handle it on my own now, thanks!!
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
(√2 + √7  √10)[(√2 + √7 + √10) (2√14 + 1)] \[\large{(\sqrt{2}+\sqrt{7}\sqrt{10})(\sqrt{2}+\sqrt{7}+\sqrt{10})(2\sqrt{14}+1)}\] \[\large{(9+2\sqrt{14}10)(2\sqrt{14}+1)=(2\sqrt{14}1)(2\sqrt{14}+1)=561=55}\]
 one year ago

mathsloverBest ResponseYou've already chosen the best response.3
nice to hear best of luck
 one year ago
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