so here's the question..
y = x^2/ (1+x)^1/2
and the answer is 4x-3x^2 / 2(1+x)^3/2
now i got the numerator but halfway through the working, the solutions said that the numerator and denominator had to be multiplied by 2(1+x)^1/2
and so resulting in with the overall denominator of 2(1+x)^3/2
can someone please explain to me why it had to be multiplied by 2(1+x)^1/2? thank you
c3 differentiation help needed - quotient rule Watch
- Thread Starter
- 27-12-2010 15:50
- 27-12-2010 16:01
- 27-12-2010 16:02
Well, the quotient rule is basically
(vdu - udv)/v^2 yeah?
When you work out udv, you need to differentiate (1+x)^1/2. When you do that, you get 0.5(1+x)^-1/2. In order to get rid of that negative power, they multiply the numerator and denominator by (1+x)^1/2, so the fraction stays the same, but it becomes more simplified.