!! Maths HL paper 1 2016 - Before and After

skippy1977

Tuttsy wrote: »

Since there's been a lot of speculation about what's right and what's not, I've tried to verify people's answers to make this list of (hopefully) correct solutions. I left out anything that was just a wordy explanation or where you had to fill in boxes or graphs on the paper. I've done my best to make sure these are right but there could definitely be mistakes in here.

If you find anything you disagree with, please point it out.

Agree with all this....though I had a small mistake in the logs question...accidentally brought down the 2 in front of the log before I separated the a and 9....and I left 8(a)(iv) in square form...cos I was too lazy to multiply out....which I just did now and it's the same as yours. Thanks for posting this.

malnurtured

skippy1977 wrote: »

Agree with all this....though I had a small mistake in the logs question...accidentally brought down the 2 in front of the log before I separated the a and 9....and I left (a)(iv) in square form...cos I was too lazy to multiply out....which I just did now and it's the same as yours. Thanks for posting this.

I was too lazy to square it out too, I left it in the 'completed square' form, do you lose marks for that? Didn't think it was worth the effort

Seaaan

Tuttsy wrote: »

Question 8
a)(i) 4.529
(ii) 52°
(iv) -0.274x^2 + 1.467x + 2 (not 100% sure about this one)
.

For the quadratic I used the point she threw it from and the point of the basket (even though by the diagram the basket wasn't in the same place?), did simultaneous equations and ended up with -.2746x^2 + 1.469x + 2

Wonder if that's right

medhopeful16

Tuttsy wrote: »

Question 6
a) 8x + 16
b)(i) Sin(1/x) - (Cos(1/x))/x
(ii) 0.15

If you find anything you disagree with, please point it out.

Where does the minus come from in Q6 b?
When you differentiate sin doesn't it go to cos not -cos?

A97

The derivative of 1/x is -1/x^2. That's where the minus comes from.

The solution is here:

https://www.symbolab.com/solver/step-by-step/%5Cfrac%7Bd%7D%7Bdx%7D%5Cleft(xsin%5Cleft(%5Cfrac%7B1%7D%7Bx%7D%5Cright)%5Cright)

It's only one question so don't worry about it. If you're a med hopeful, you probably have Physics and/or Chemistry to study for! Good luck.

DublinArnie

I wonder if the completed square format of the equation would be accepted.

A97

I don't know why it wouldn't be accepted. That equation could have been found using the y = a(x - h) + k method or you could have translated the points from the other parabola to have three equations and three unknowns e.g. y = ax^2 + bx + c