Edexcel C3 June 2016 - Unofficial Mark Scheme

Im pretty sure the p in 5ii was 1?
Does anyone remember the question?

Here is the proof, each step represents a possible mark.

For question 2b. I got that x>(plus or minus)sqrt5. So x is greater than -root5 and also greater than root5, so writing x>-root5 would be wrong? as only x>root5 is required

Does anyone have any idea what 63 marks might be?

Plus the question where you had to find the equation of the line, did anyone get the gradient of the the tangent -4, therefore the gradient of the normal was 1/4?

Thanks

I got a gradient of the tangent as 10, so the gradient of the normal was -1/10, I think I got y-16=-1/10(x-3) and then simplified, I don't think you need to simplify it though as it didn't say in the question so leaving it in that form would be fine I guess

I got a gradient of the tangent as 10, so the gradient of the normal was -1/10, I think I got y-16=-1/10(x-3) and then simplified, I don't think you need to simplify it though as it didn't say in the question so leaving it in that form would be fine I guess

ok guys so i have a question about how many marks i'd get for question 6, where you had to find the values of A and B and then the eqn of the normal.

I tried part a properly a few times and could not get it for some reason, but then i looked at part b. i noticed if you differentiated the given function then you'd get rid of A. I put the original eqn into my calculator to find the gradient of the tangent at the point (2), then obviously found the normal gradient and equation.
Through this i could create and equation for B, so work out that B=4. then just sub this into the original eqn to find A=3. i just wrote 'comparing coefficients gives...' for the 'working' (though I didn't cross anything out, but i'm pretty sure it was all wrong anyway)

obviously this is a very dodgy method, how many marks am I looking at? thanks.

If I remember the question, to find A and B you had to do long division to find out the remainder which let you find A and then you could find the B so you had the simplified function. Then differeentiate that, sub in the x=3 into original function to get the y value which was 16. Put x=3 into dy/dx which came as 2, then you're finding the normal so m=-1/2. Then work out the equation like normal.