TCS
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Logical Reasoning
Decision Making and Problem Solving
the maximum possible value of (6^x-36^x) over all real values of x is
options 1) infinity 2)0 3)1 4)1/4 5) 1/2
Read Solution (Total 6)
-
- 1/4
(6^x-36^x)
Differentiating (6^x-36^x) w.r.t x and equating to zero, we get
6^x * log x - 36^x * log 36 = 6^x -(6^2x)*(2log 6) =0
6^x =1/2
putting this value of 6^x in (6^x-36^x)
1/2-1/4= 1/4 - 12 years agoHelpfull: Yes(19) No(3)
- y = 6^x-36^x
let p=6^x
then y= p-p^2
y= 1/4-(p^2-p+1/4)
y= 1/4-(p+1/2)^2
for max y, (p+1/2)=0
Max y=1/4-0
Max y=1/4 - 12 years agoHelpfull: Yes(12) No(0)
- 4) 1/4
explanation -
let 6^x = y (where y>=0), 0 y = 1/2
again, by taking double derivative
d^2f(y)/dy^2 = -2
so, f(y) has max value at y = 1/2
=> so max value = 1/2-(1/2)^2 = 1/4 - 12 years agoHelpfull: Yes(2) No(3)
- ans. is 0..bcoz 0 is a real no.
- 12 years agoHelpfull: Yes(1) No(7)
- option no. 3
by equating single derivative of given expression to zero ,we can get extreme values of the expression
by substituting this in double derivative we can get max value - 12 years agoHelpfull: Yes(1) No(1)
- let, y=(6^x-36^x)
for maximum value of y
dy/dx=0
6^xln6-36^xln36=0
x=log(12) with base 6
after putting this in y we get y=1/2 ans hence option 5 is correct - 12 years agoHelpfull: Yes(0) No(6)
TCS Other Question
3.2-(5-33[4/2+1]) =
a)-21 b)32 c)45 d)60 e) 78
Cubes c1,c2,c3.....and Spheres s1,s2,s3,....are defined in the following way.
-s1 has radius 4cm.
-For each n>0, Cn is inscribed in Sn and Sn+1 is inscribed in Cn(ie c1 is inscribed in s1,s2 is inscribed in c1,c2 is inscribed in s2 and so on)
Let Vn be the sum of the volumes of the first n cubes c1,c2,c3....Cn.Then as n->infinity Vn approaches.
options i)384(1+3root3)/13 2)64(1+3root3)/13 3) 128(1+3root3)/13 4) infinity , ie Vn is unbounded.