All Junior Cert Mathematics posts
• #### Maths Paper 1?? highes

What answer did you all get for the questions about the prime numbers-what were the two reasons why the boys formula was incorrect and why did the scientists formula only work for numbers below 41? Oh also, what did people say for the liner, quadratic or exponential question??Why?? How does everybody think the paper went!??

1. #### study person

Paper was alright..didnt get a few question parts. I got Pi as the prime number, formula was incorrect cause it didnt give all prime numbers (skipped 3), and all formula results werent prime numbers e.g. 35, I said it was quadratic (second difference was constant), Didnt understand how to get the formula and rate of change on the currency question:(:(:(

2. #### highes

I said it was exponential, i don't think that the second difference was constant, because the ball began to descend i.e.decrease? I .I also said your point about some of the numbers not being prime numbers and i said that if you sum in another prime number to the equation but then it said to add one in the equation, then you would get an even number which is not prime as it is divisible by 2? I didn't get the currency exchange question either! i completely guesses and said like 4P(pounds)=5.2E(euros) or something like that!!!

3. #### study person

I got a constant second difference of 0.8 because the difference between 4 and 5 (increasing) is the same as the difference between 5 and 4 (decreasing) i.e. 1 ....? for the currency i guessed too! €1=£.83 i think :/:/:/ ahwell its too late now!!;)

4. #### Ellenmcgh

the second difference was a constant of -0.8

5. #### MysticManiac

For the prime-number questions I said that it didn't show 2 and 3, and that 1 isn't a prime number because a number must divide into TWO different numbers to be a prime number. For the 41 number, I said that for 41 squared which is 1681, that 1, 41 and 1681 divide into it so it's not a prime number. I said exponential because at first, it was quadratic but then it changed

@studyperson - The constant difference wasn't constant. It was the same for the first few, but then it changed, so I said exponential

6. #### study person

When did it change?

7. #### MysticManiac

0.3 -- 3.4 -- 5.7 -- 7.2 -- 7.9 - 7.8 - 6.9. First difference was 3.1, 2.3, 1.5, 0.7, 0.1, 0.3. The Second difference was 0.8, 0.8, 0.8, 0.6, 0.2. It was only the same for the first 3, but then it changed.

8. #### study person

The last two First differences I got were -0.1 and -0.3 which got a second difference of 0.8

9. #### 11ND - CCM

I got all the same stuff as Mystic. He is right in saying that the graph was exponential, it started to change as it desecended.

10. #### study person

how did I get quadratic and a constant second difference then???:L