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Question help as maths

Got this in my CCEA AS C1 exam today. Need to know what the answer would be.

(x-p)(x-q)=m^2

Show that the equation has real roots
It's a quadratic, so rearrange into a more familiar form.
what method do you know to test if an equation has real roots?
Reply 2
Original post by ralph9694
It's a quadratic, so rearrange into a more familiar form.
what method do you know to test if an equation has real roots?


I expanded it and used b2 -4ac but I was lost from there and ended up solving for p in terms of q and q in terms of p. I know I am retardedog-joe-weller-29838-compressed.jpg.jpeg
no your not.
what was the expression for the discriminant?
Reply 4
Original post by ralph9694
no your not.
what was the expression for the discriminant?


b^2 -4ac
Original post by Biggly
Got this in my CCEA AS C1 exam today. Need to know what the answer would be.

(x-p)(x-q)=m^2

Show that the equation has real roots


All you need to do is SHOW that the eq. has real roots, you don't necessarily need to find them here.

x2(p+q)x+pqm2=0x^2-(p+q)x+pq-m^2 = 0 from the eq.

Hence for real roots we need that b24ac0b^2 - 4ac \geq 0. Do we have that here??

Clearly, (p+q)24(1)(pqm2)=p22pq+q2+m2=(pq)2+m2(p+q)^2 - 4(1)(pq-m^2) = p^2 -2pq + q^2 + m^2 = (p-q)^2 + m^2

and you are summing two squares, hence obviously this is a +ve quantity.
Reply 6
Original post by RDKGames
All you need to do is SHOW that the eq. has real roots, you don't necessarily need to find them here.

x2(p+q)x+pqm2=0x^2-(p+q)x+pq-m^2 = 0 from the eq.

Hence for real roots we need that b24ac0b^2 - 4ac \geq 0. Do we have that here??

Clearly, (p+q)24(1)(pqm2)=p22pq+q2+m2=(pq)2+m2(p+q)^2 - 4(1)(pq-m^2) = p^2 -2pq + q^2 + m^2 = (p-q)^2 + m^2

and you are summing two squares, hence obviously this is a +ve quantity.


Now what would you say if I told you I completely disregarded that M^2. And then did the entire thing without it. would you say I am thick?
Reply 7
Since CCEA do "positive marking" and follow through marking, I wonder if they would be so kind as to give me some marks.
Original post by Biggly
Now what would you say if I told you I completely disregarded that M^2. And then did the entire thing without it. would you say I am thick?


I'd say you lose one, maybe two marks :biggrin:
Reply 9
Original post by RDKGames
I'd say you lose one, maybe two marks :biggrin:


The question was out of 5 or 6. Also, I went on to find a value of p in terms of q and a value of q in terms of p. I just can't see myself getting anything from this.

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