Not really(Original post by 01234567)
c3 Jan 2010.
f(x) = 2 − (√3x + 1)^1/3
Find the set of values of x for which f(x) = |f(x)|.
I equated fx to itself and to -fx.. Is this the right way to do the question?You have to consider the point at which f(x) = 0The mark scheme has the answer down as x is less or equal to 7.
when f(x)>0, |f(x)| does not change so |f(x)|= f(x)
if f(x)<0, then |f(x)|=-f(x) which is no good to you
OCR A2 maths january, C3/C4/S2 question. Watch
- 05-01-2013 20:12
(Original post by 01234567)
- 05-01-2013 20:13
5)ii) Find an expression for the second derivative and hence ﬁnd the value of
the second derivative at the stationary point.
I got the right answer up to a point in the mark scheme.
To find out the second derivative at the stationary point is this the same as just equating dy/dx = 0?
From the mark scheme, they appear to have substituted x = 0 to find out the stationary point from the equation... so, is this different for the second derivative?
- Thread Starter
- 05-01-2013 20:25
- 05-01-2013 20:26
That is why you use x=0