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Mathematics: Post your doubts here!

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Q. A geometric progression has the first term 4, and common ration (2x-3) , find the set of values of x for which the geometric progression has a sum to infinity.

How o_O?
 
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Q. A geometric progression has the first term 4, and common ration (2x-3) , find the set of values of x for which the geometric progression has a sum to infinity.

How o_O?
r<1 if sum to infinity exists
solve this inequality using the vlaue of r u have : - (2x-3) and u'll get ur range... i think :p
 
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Hey can any1 give me right answers for oct 2012 paper 13. The ms is confusing ,not all answers in there
 
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yeah most of the time you make the same mistake the students who took the exam are making so er can help
 
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thanks al
i) y=0
0=x(x-2)
x=0 and x=2
a=2 (since its visible from the graph that a cant be zero)

ii) b is a max pt.
dy/dx = 3x^2 -8x +4 =0
x= 2 and x= 2/3

b=2/3 (since both turning pts are visible from the graph and b is the first turning pt so i ll take the smaller value of x) (beside a was 2) :D
s
iii) integrate the function with limits 0 and 2

iv) It is asking for the minimum value of dy/dx... dy/dx= 3x^2 - 8x +4
thus yu just have to find minum value of that quadratic function
Two ways to do it .. Do completing squares or just derivate it again and equate it to zero .. u shall get x substitute that x to the dy/dx equation and that will be yur anser


Thanks alot :) many thanks :D but can u just tell me when is it necessary for us to double derivate it and put it equal to zero ?
 
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