Elitmus
Exam
Numerical Ability
log(xy^3)=a
log(x^2y)=b
find the value of logy/logx
Read Solution (Total 4)
-
- log x +logy^3=a
log x + 3*log y=a--------1
now take second expression
log x^2 + log y=b
2*logx + log y=b---------2
multiply equation 1 by 2 and solve the equation 3 & 2
2*log x + 6*log y=2*a-----3
2*logx + log y=b
--------------------------
5*log y= 2a-b
log y= (2a-b)/5-----------4
put the value of 4 in 2, we will get
2*logx + (2a-b)/5 =b
2*logx = b-(2a-b)/5
2*logx = (5b-2a+b)/5
2*logx = (6b-2a)/5
2*logx = 2(3b-a)/5
log x= (3b-a)/5------------5
now,
log y/log x= (2a-b)/(3b-a)
- 10 years agoHelpfull: Yes(6) No(4)
- log(xy^3)=a
logx+log(y^3)=a
logx+3logy=a-----------1
next
log(x^2y)=b
log((x^2)+logy=b
2logx+logy=b-----------2
equation 1 divided by 2
(logx+3logy)/(2logx+log y)=a/b
now divided by logx
(1+3t)/(2+t)=a/b where t=logy/logx
t=(2a-b)/(3b-a)
logy/logx=(2a-b)/(3b-a) - 10 years agoHelpfull: Yes(4) No(1)
- Answer is (2ay-b)/3b
log(x)+3log(y)=a........eqn1
2ylog(x)=b..................eqn2
dividing eqn1/eqn2 we get;
1/2y + 3log(y)/2ylog(x) = a/b
solving further log(y)/log(x)= 92ay-b0/3b - 10 years agoHelpfull: Yes(0) No(0)
- log(y)/log(x)=(2a-b)/(3b-a)
- 10 years agoHelpfull: Yes(0) No(0)
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