Maths question

OP

Your aim is to split what's inside the surd into factors - ideally you want to find a factor that is a square number because then you can take a whole number factor outside the root sign to simplify it.

But do they have to be the same number if you want to simplify. For example: 2root5+4root5 is 7root5 but you can't add together 2root5 and 3root7 because the number in the root isn't the same? At least, that's my understanding.

Reply 21

davros

16

Original post by Year11guy

But do they have to be the same number if you want to simplify. For example: 2root5+4root5 is 7root5 but you can't add together 2root5 and 3root7 because the number in the root isn't the same? At least, that's my understanding.

That's quite correct - you want to simplify each term as much as possible, and then hopefully you can combine one or more of them at the end. Sometimes it will be possible to combine all of them; other times you won't be able to :smile:

EDIT: I think you meant 6root6 in your example :smile:

Reply 22

bobby000

√20=√4x5=2 √5
2√45=2√9x5=6√5
√80=√16x5=4√5
Therefore ,answer is 4√5

Reply 23

davros

16

Original post by bobby000

√20=√4x5=2 √5
2√45=2√9x5=6√5
√80=√16x5=4√5
Therefore ,answer is 4√5

I think the OP's got it now, but please don't post full solutions in future - it's against the forum rules :smile:

Reply 24

username1050473

14

Original post by davros

I think the OP's got it now, but please don't post full solutions in future - it's against the forum rules :smile:

So we have to lead them on to the answer? Like giving just the next step or giving an example? Or can we link to Wolfram too? :wink:

Reply 25

davros

16

Original post by sarcasmrules

So we have to lead them on to the answer? Like giving just the next step or giving an example? Or can we link to Wolfram too? :wink:

You can:
give them hints / suggestions of things to try
ask them what they think the first/next step should be
give them an example using different numbers
ask them where they're stuck / what they've tried / can they show some working

(You could link them to Wolfram, but all that will do is let them calculate the answer, it won't help them to understand what's going on!)

Generally, if you give someone a full solution they just end up getting the answer to that one question, and you've no idea whether they've really understood or not, or fixed any misconceptions they may have :smile:

Reply 26

username1050473

14

Original post by davros

You can:
give them hints / suggestions of things to try
ask them what they think the first/next step should be
give them an example using different numbers
ask them where they're stuck / what they've tried / can they show some working

(You could link them to Wolfram, but all that will do is let them calculate the answer, it won't help them to understand what's going on!)

Generally, if you give someone a full solution they just end up getting the answer to that one question, and you've no idea whether they've really understood or not, or fixed any misconceptions they may have :smile: