Re: HSC 2015 3U Marathon
well, as Carrotsticks said, any finite number of terms may not uniquely determine a pattern.
but the formula T_n=\frac{7n^2-5n}{20(2^n-1)} definitely gives one of the possible patterns
Re: HSC 2015 3U Marathon
only listing three terms, a pattern may not be clearly defined. like the denominators: 10, 30, 70, ... the next one could be 70+60=130, could also be 70+80=150, could even be something else
Re: HSC 2015 4U Marathon
new question
$ Prove that $ P(x)=x^5-ax+1=0 $ has three distinct real roots if and only if $ a>5\left(\frac{1}{2}\right)^{8/5}.
Re: MX2 2015 Integration Marathon
good start, but you do not need to actually integrate it, you just need an estimation, why not try to apply the comparison property of definite integrals
Re: MX2 2015 Integration Marathon
just to fix the latex problem
\int \frac{1+x}{\sqrt{1-x^{2}}} dx \\ =\frac{-1}{2} \int {\frac{-2}{\sqrt{1-x^{2}}} + \frac{-2x}{\sqrt{1-x^{2}}} \\ ={\frac{-1}{2}} (-2sin^{-1}(x) + 2 \sqrt{1-x^{2}})
is this what you wanted ?
Re: MX2 2015 Integration Marathon
\int_{0}^{100\pi} \sqrt{cos^{2}(x) + sin^{2}(x) - cos^{2}(x) + sin^{2}(x)} dx=\int_{0}^{100\pi} \sqrt{{2}} \sqrt{sin^{2}(x)} dx=\int_{0}^{100\pi} \sqrt{{2}} |sin(x)|dx
$ Now, the graph of $ |sin(x)| $ will repeat every pi/2 interval as it is a reflection...
Re: HSC 2015 4U Marathon - Advanced Level
i got \frac{19}{36} for part (i) and \frac{3}{7} for part (ii). i am not sure this is true or not, because i didn't use those facts.