Qualification > Math
Additional Math Help HERE ONLY...!
syedz123:
--- Quote from: A@di on May 31, 2010, 05:41:21 pm ---i) substitute 0 for velocity.. 0 = cos 4t
4t = y
cos y = 0
y = cos-1 0 = 90
here its 90 degrees, but v gotta take it in radians, so Pi radians = 180 degree
4t = 0.5pi radians
t = pi/8
t = pi/4
ii) differentiate v = k cos 4t
k = a
cos 4t = b
d/dx(a) = 0
d/dx(b) = -4sin4t
dv/dx = a(db) + b(da) = -4ksin4t + 0 = -4k sin 4t
iii)
k = 3
iv) make a table and plot the points.
v) integration of 3cos4t with limits pi/24 and 0
--- End quote ---
sorri A@di bt i still dnt get da second one...it says find da position vector of P at 12:00...so do we jst leave da answer as -4k sin 4t? dont we hv to use da '12:00' in this and da answer shuld b in a vector f0rm?? c0z its findin da position vector...sorri i told u am a weak add math student :-\
Ghost Of Highbury:
Dude the question u r referring to is question 9...the one with the quote is different answer which is question 12...
syedz123:
--- Quote from: A@di on June 01, 2010, 06:02:49 am ---Dude the question u r referring to is question 9...the one with the quote is different answer which is question 12...
--- End quote ---
omgness!! LOL wts happning to me...sorri man lol Thanks agen :D
syedz123:
can someone plz help me wiv this
Find the coefficient of x4 in the expansion of
(i) (1-x/4)(1+2x)^6
and integration 4rm q7 (ii) may/june 09 p1
plz explain step by step
cooldude:
--- Quote from: syedz123 on June 02, 2010, 12:59:28 pm ---can someone plz help me wiv this
Find the coefficient of x4 in the expansion of
(i) (1-x/4)(1+2x)^6
--- End quote ---
k the first q-->
first expand (1+2x)^6--> 1+12x+60x^2+160x^3+240x^4........
now we need the coefficient of x^4--> (1-(x/4))(1+12x+60x^2+160x^3+240x^4........)
now look at the above line ive typed, look for powers of x which multiply to give x^4, we see that 1 and 240x^4 multiply to give x^4 i.e. 240x^4, we also see that the product of -x/4 and 160x^3 is -40x^4 which again has x^4, so now we have 2 terms which have x^4, -40x^4 and 240x^4, so when we add them we get 200x^4, and the coefficient of this is 200, the answer required, the way i told u of finding terms which multiply to give x^4 is much easier than expanding the whole thing, u can do that for this q, as it will give u a clear idea of what ive done, and ive only expanded (1+2x)^6 uptil x^4 as that is what we need and not the whole expansion
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