Latest Microsoft Aptitude Question SOLUTION: If m^2 + m^-2=23 then find m^3 + m^-3

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If m^2 + m^-2=23
then find
m^3 + m^-3

Asked In Microsoft Pawan Pandey (9 years ago)

Unsolved Read Solution (8)

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Read Solution (8) :

saikiran Gandham  (9 years ago)

a^3+b^3=(a+b)(a^2+b^2-ab)
here a=m,b=1/m;
(m+1/m)(23-1);
and (m+1/m)=(m2+1/m2+2)^1/2=5;
=5*22=110

Is this solution Helpfull? Yes (10) | No (1)  

garima singh  (8 years ago)

110.
sqauring m+1/m we get the value of m+1/m.
cubing m+1/m we get the required value

Is this solution Helpfull? Yes (3) | No (1)  

shobika  (6 years ago)

(m+1/m)^2= m^2+1/m^2+2
m^2+1/m^2=23
m+1/m=5
then
make use of in m^3+m^-3
so answer is 110

Is this solution Helpfull? Yes (3) | No   

satya prasanna.chitakana  (7 years ago)

0 because 3m-3m=0 whatever may be value of m

Is this solution Helpfull? Yes (2) | No (5)  

Divya Batra  (6 years ago)

answer is 110
solution is:-
(m + (1/m))^2=m^2 + (1/m)^2 + 2*m*(1/m)
(m + (1/m))^2=23 + 2*m*(1/m)=23+2=25
so, (m + (1/m))=sqrt (25)=5

now,
(m + (1/m))^3=m^3 + (1/m)^3 + 3*m^2*(1/m) + 3*m*(1/m)^2
5^3 - 3*m^2*(1/m) - 3*m*(1/m)^2 =m^3 + (1/m)^3
5^3 - 3*(m +(1/m)) =m^3 + (1/m)^3
5^3 - 3*5 = m^3 + (1/m)^3
125-15=m^3 + (1/m)^3

therefore, m^3 + (1/m)^3=110

Is this solution Helpfull? Yes (1) | No   

Bhavana Gollapudi  (6 years ago)

from (a+b)^2 formula,we can find (m+1/m).From (a+b)^3,we can find the solution. Answer is 110

Is this solution Helpfull? Yes (1) | No   

swathi mundru  (6 years ago)

m^2+m^-2=23 ==> m+m^-1=5
m^3+m^-3=(m+m^-1)^3-3(m+m^-1) = 125-3(5) = 125-15 = 110

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ADITYA VEER VIKRAM SINGH  (6 years ago)

110 and -110

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