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Mathematics: Post your doubts here!

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Got it :D

Now at maximum speed, acceleration is 0, obviously because it can no longer go faster.
So you must differentiate to get the acceleration function, and equate it to 0, to get t.
First expand the velocity formula... from k(60t^2 - kt^3) to 60kt^2 - kt^3..
v = 60kt^2 - kt^3 ... Differentiate this.
a = 120kt - 3kt^2
120kt-3kt^2 = 0
120kt = 3kt^2

Divide both sides by kt

120 = 3t
t = 40

Now go back to the velocity function, and replace v with 6.4, as given in the question, and t with 40.

k(60(40)^2 - 40^3) = 6.4
k = 6.4/32000
k= 0.0002
 
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d1=PQ=OQ-OP=(-2 4 1)-(1 0 -1)=(-3 4 1)
d2=PR=OR-OP=(4 2 1)-(1 0 -1)=(3 2 2)
Find the cross product of d1 and d2
ie ( 6 9 -18) it can also be written as (2 3 -6)
Now
rn=an
(x y z)(2 3 -6)=(3 5 -6)(2 3 -6) where a is OS( position vector of S)
the equatn is 2x +3y-6z=8

this is a very useful formula, try to remember it
modulus of (ax1+ by1+cz1-d)/root of (a^2+b^2+c^2) see winter 2012...its given there
mod of{(2(3)+3(5)-(-6)-8)}/root of(2^2+3^2+6^2)
and the ans comes to 7 units
if u dnt understand feel free to ask iKhaled
 
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d1=PQ=OQ-OP=(-2 4 1)-(1 0 -1)=(-3 4 1)
d2=PR=OR-OP=(4 2 1)-(1 0 -1)=(3 2 2)
Find the cross product of d1 and d2
ie ( 6 9 -18) it can also be written as (2 3 -6)
Now
rn=an
(x y z)(2 3 -6)=(3 5 -6)(2 3 -6) where a is OS( position vector of S)
the equatn is 2x +3y-6z=8

this is a very useful formula, try to remember it
modulus of (ax1+ by1+cz1-d)/root of (a^2+b^2+c^2) see winter 2012...its given there
mod of{(2(3)+3(5)-(-6)-8)}/root of(2^2+3^2+6^2)
and the ans comes to 7 units
if u dnt understand feel free to ask iKhaled
i dont understand y did u find the cross product of d1 and d2..can u pls explain this part?
 

Maz

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Please Nov2012 v.13 no.6 i . no.7 ii , 8 iii ) , 9 all , 10 iii
11 ) ii and iv urgentlyyy .
I'll answer your questions one by one
6i) gf(x) = 1
f(x) = 1/2 x +1/6 n [take that n as pi please :D ]
g(1/2 x + 1/6 n) = 1
cos ( 1/2 x + 1/6 n ) = 1
1/2 x + 1/6 n = cos-1( 1)
1/2 x + 1/6 n = 0
1/2 x = -1/6 n
x = 2(- 1/6 n )
x = -n/3
 
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