Mathematics: Post your doubts here!

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yubakkk

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|z| < |z − 2 − 2i| how to plot this in argand diagram??
please help me with expalanation
 
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Helpneeded007

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aaakhtar19 said:
4(ii)
Friction = u*R
4cos(30)=u*[10-4sin(30)]
u=[4cos(30)/8]=0.433

5(ii)
As B continues to move for 0.3 sec , surely after those 0.3 sec B's velocity would be zero
so V=U+at
O=U -10*0.3
U=3
"3" is the speed with which A hits teh floor
So,
2as=V^2-U^2
2*2*s=3^2-O^2
s=2.25

Hope u got them ;)
Click to expand...
Yea got it.Thx alot man.1 more thing i actually meant 4(i) and not 4(ii) so could you tell Me how to find the value of C please.
 
bamteck

bamteck

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Please help me with the following AP questions :
1. Find the sum of all integers from 1 to 200 that are divisible by 7.
2. Find the sum of all integers from 1 to 200 inclusive that are not multiples of 5.
3. Find the sum of all multiples of 5 between 100 and 300 inclusive.
4. In a arithmetic progression of 25 terms, the 10th term is 23 and that the sum of the last 10 terms is 440. find the sum of the first 10 terms.
 
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hm12

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This thread was quite helpful during P1 prep but i see no one helping quite a lot for M1 please someone who is good at mechanics help there are so many ppl with problems :(
 
princesskt

princesskt

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7i box remain at rest when <3150 sofriction component=3150
R=weight =4500 mew=3150/4500 0.7
ii)for no sliding friction component m ust be>ma
.2*2000>200 a
iii) P-F=MA
P-(0.7*4500)=450*2
a=2 used becoz no sliding
 
princesskt

princesskt

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hm12 said:
This thread was quite helpful during P1 prep but i see no one helping quite a lot for M1 please someone who is good at mechanics help there are so many ppl with problems :(
Click to expand...
i ans your ques .....................................
 
leadingguy

leadingguy

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kagome said:
M/J 2010 P32 Q 8(ii). How to do?? Thx...
Click to expand...



z = 1 + cos 2θ + i sin 2θ

1 + cos 2θ.... this is the real part of Z

i sin 2θ ..... this is the imaginary part of Z

now for 1/Z

1/(1 + cos 2θ + i sin 2θ ) ........ solving fractions to get ans in frm of x +yi needs the multiplicatioon of numenatr and denominatr by conjugate base.

so nw mutiply by cnjugate base

1*( 1 + cos 2θ - i sin 2θ )/(1 + cos 2θ + i sin 2θ ) *(1 + cos 2θ - i sin 2θ)

( 1 + cos 2θ - i sin 2θ )/(1 + cos 2θ + i sin 2θ ) *(1 + cos 2θ - i sin 2θ) ...... now solve fr the denominator to simplify.

there are more than one method fr simplifiyng the denominator... we wil uise (a)^2 -(b)^2

consider
1 + cos 2θ = a
i sin 2θ = b
now look the denominator .... (1 + cos 2θ + i sin 2θ ) *(1 + cos 2θ - i sin 2θ) = (1 + cos 2θ )^2 -( i sin 2θ)^2

now open the denominator

( 1 + cos 2θ - i sin 2θ )/(1 + cos 2θ )^2 - ( i sin 2θ)^2

( 1 + cos 2θ - i sin 2θ )/ (1 +2cos2θ + cos^22θ) - (-1sin^22θ)

( 1 + cos 2θ - i sin 2θ )/ (1 +2cos2θ + cos^22θ +sin^22θ)


now separate the real and imaginary parts

(1 + cos 2θ)/(1 +2cos2θ + cos^22θ +sin^22θ) - ( i sin 2θ )/ (1 +2cos2θ + cos^22θ +sin^22θ)

real part we get is (1 + cos 2θ)/(1 +2cos2θ + cos^22θ +sin^22θ)

substitute values of θ in this part u wil get the same ans. every time;) this shows that the real part is constant at every value of θ:)
 
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