Search results

Hey guys, can I get a rough idea as to what ATAR I might get? My ranks are: Adv. English - ~65-70/121 Economics - 2/50 Chemistry - ~15/88 3U Maths - 8/100+ 4U Maths - 1/43 School rank is in the mid 20s. Ideally, I'd be looking for around 97+, but i only really need around 95...

Re: MX2 Integration Marathon let u=e^x du = e^x * dx I = integral{(e^x * e^x)/(e^x+1)}dx = integral{u/(1+u)}du = integral{1-(1/(1+u)}du = u - ln(1+u) = e^x - ln(e^x+1) + C

for the first one, the answer is 9C4*5C4*1C1 divided by 2 i assume you know why you multiply those combinations, but you divide by 2 because the teams aren't distinguishable from one another for the second one, we can assume 3 conditions let the 2 players be A and B first condition: A is...

the inflation rate is calculated by the CPI of the previous year subtracted from the CPI of the current year, divided by the CPI of the previous year. then that value is multiplied by 100 to give you the inflation rate as a percentage. do that for year 1 to year 2 and year 2 to year 3 to compare...

Re: MX2 Integration Marathon sqrt(1+sin2x) = sqrt(sin^2(x) + cos^2(x) + 2sinxcosx) = sqrt(sinx+cosx)^2 =sinx+cosx .'. integral sqrt(1+sin2x) dx = integral (sinx+cosx) dx = -cosx + sinx + C not sure how to do the second one

the indefinite integral of 0 is a constant - think when you derive the equations of projectile motion in regards to horizontal motion the area under the curve idea can be applied with the idea of a definite integral, except you're finding the area of the curve bound by the x-axis and the line...

you can find the number of arrangements where 2 cannot sit together by subtracting the number of arrangements where these 2 do sit together from the total number of arrangements with no restrictions number of arrangements with no restrictions is 6! number of arrangements where 2 people sit...

the first thing would be to differentiate the curve, so we would get dy/dx = -x^2 when we substitute values for x into dy/dx, we are basically finding the gradient of the tangent to the curve curve at that particular x-value, for example, in this case, if we were to substitute x=3 into dy/dx...

Re: HSC 2012 Marathon :) Using cosine rule, cosA = [b^2 + c^2 - a^2]/2bc 2cos^2(A/2) - 1 = [b^2 + c^2 - a^2]/2bc 2cos^2(A/2) = [b^2 + c^2 - a^2]/2bc + 1 = [b^2 + c^2 - a^2 + 2bc]/2bc = [(b+c)^2 - a^2]/2bc = [(b+c+a)(b+c-a)]/2bc = [p((p-a)-a)]/2bc = [p(p-2a)]/2bc cos^2(A/2) =...

Re: 2012 HSC MX2 Marathon integral[(sinx-cosx)/(2+2sin2x)] = integral[(sinx-cosx)/(1+2sinxcosx+sin^2x+cos^2x)] = integral[(sinx-cosx)/(1+(sinx+cosx)^2)] let u=sinx + cosx du = cosx - sinx dx .'. integral[(sinx-cosx)/(1+(sinx+cosx)^2)] = -integral[1/(1+u^2)] = -arctan(u) = -arctan(sinx +...

Haha, no problem! good luck for your trials too :)

the rate of the growth of the population being proportional to itself just means that dP/dt = kP where k is some constant. since the population is growing, k is positive as the rate of growth must always be positive in order for the population to grow now, P=Ae^kt, where A is the starting...

when x=0, x/arctanx = 0/0 which is undefined i know the limit as x approaches 0 is 1, but because it is undefined when x=0, shouldn't it be an open circle at (0,1)?

it's also an open circle when x=0

P = I/[RI + (1-RI)e^(-kt)] dP/dt = [0 - I(-k(1-RI)e^(-kt)]/[RI + (1-RI)e^(-kt)]^2 using quotient rule = [kI(1-RI)e^(-kt)]/[RI + (1-RI)e^(-kt)]^2 now, P[RI + (1-RI)e^(-kt)] = I [RI + (1-RI)e^(-kt)] = I/P [RI + (1-RI)e^(-kt)]^2 = I^2/P^2 --- (1) [RI + (1-RI)e^(-kt)] = I/P (1-RI)e^(-kt) = I/P -...

LHS = tan(pi/4 + x) = [tan(pi/4) + tanx]/[1-(tan(pi/4)*tanx)] = [1 + tanx]/[1 - tanx] since tan(pi/4) = 1 = [1 + sinx/cosx]/[1-sinx/cosx] multiplying top and bottom by cosx, = [cosx + sinx]/[cosx - sinx] = RHS

hmm, yeah, i'd probably count it as an opinion too... thanks! :D

oh yeah, sorry about that, don't really know what i was thinking...

yes, when you're finding the concentration of hydrogen ions, you multiply the concentration of sulfuric acid by 2, then use -log[H+] to get the pH. however, remember that it's not -log[2H+], it's just -log[H+], but [H+] = 2[H2SO4] and also, yes it will mean that sulfuric acid has a lower pH...

At the NSW State elections, a pre-poll survey found that 50% of the electorate were in favour of the sitting member, 40% were opposed and 10% were undecided. If three people are selected at random, find (giving your answers as percentages to the nearest whole number): (i) the probability...