# how to find the value of k given two doWatch

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#1
Question paper: https://filestore.aqa.org.uk/resourc...-73572-SQP.PDF
Mark scheme: https://filestore.aqa.org.uk/resourc...-73572-SMS.PDF

I don't understand the answer for question 6(a).
I don't understand why you have to MULTIPLY the two roots to get the value of k.
How is this the case??
I don't get how to do 6(a) and I get even more confused when I look at the mark scheme.
0
#2
given two know values*
in the question!! sorry
0
4 days ago
#3
(Original post by ChloeYeo)
Question paper: https://filestore.aqa.org.uk/resourc...-73572-SQP.PDF
Mark scheme: https://filestore.aqa.org.uk/resourc...-73572-SMS.PDF

I don't understand the answer for question 6(a).
I don't understand why you have to MULTIPLY the two roots to get the value of k.
How is this the case??
I don't get how to do 6(a) and I get even more confused when I look at the mark scheme.
You can substitute either coordinate in the equation and get the value of k.
For the case, where the 2 roots have been multiplied to get k:
If you consider a quadratic eqt in the form of ax^2+bx+c=0 , the product of the roots = (c/a)
In this case a=1, so product of roots = c = k
However in don’t think this should be known as the previous method is much easier.
1
4 days ago
#4
(Original post by ChloeYeo)
Question paper: https://filestore.aqa.org.uk/resourc...-73572-SQP.PDF
Mark scheme: https://filestore.aqa.org.uk/resourc...-73572-SMS.PDF

I don't understand the answer for question 6(a).
I don't understand why you have to MULTIPLY the two roots to get the value of k.
How is this the case??
I don't get how to do 6(a) and I get even more confused when I look at the mark scheme.
The method of multiplying the two roots is one that further mathematicians might be inclined to adopt, and it's included in the mark scheme to take account of their using it.

As vbzi suggests, substituting either of the roots will suffice.
1
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