8
Q:

Find x if 

A) 0 B) 1
C) 2 D) None of these

Answer:   A) 0



Explanation:

         \inline \log_{\frac{1}{\sqrt{2}}}(1/\sqrt{8})=\log_{2}(4^{x}+1).\log_{2}(4^{x+1}+4)

\inline \Rightarrow     \inline \frac{\log_{2}(1/\sqrt{8})}{\log_{2}(1/\sqrt{2})}=\log_{2}(4^{x}+1).\log_{2}(4^{x+1}+4)

\inline \Rightarrow    \inline 3=\left [ \log_{2}4+\log_{2}(4^{x}+1) \right ]\left [ \log_{2}(4^{x}+1) \right ]

\inline \Rightarrow    (2+t)t = 3,    where t = \inline \log_{2}(4^{x}+1)

\inline \Rightarrow     t = -3, 1

If \inline \log_{2}(4^{x}+1)= -3, then \inline 4^{x}=-7/8 which is not possible

If \inline \log_{2}(4^{x}+1)=1, then \inline 4^{x}+1=2\: \: \: \Rightarrow 4^{x}=1

\inline \Rightarrow               x = 0

Q:

Solve the equation   ?

A) -1/2 B) 1/2
C) 1 D) -1
 
Answer & Explanation Answer: A) -1/2

Explanation:

Rewrite equation as

Leads to 2x + 1 = 0 

Solve for x : x = -1/2

Report Error

View Answer Workspace Report Error Discuss

3 184
Q:

If  = m, then  is equal to ?

A) 1/(1+2m) B) (1+2m)/2
C) 2m/(2m+1) D) (2m+1)/2m
 
Answer & Explanation Answer: B) (1+2m)/2

Explanation:

=
=

.

Report Error

View Answer Workspace Report Error Discuss

6 414
Q:

If  , then 

A) 1 B) 2
C) 4 D) 8
 
Answer & Explanation Answer: B) 2

Explanation:

Given  

Now  = 

Report Error

View Answer Workspace Report Error Discuss

7 435
Q:

If log 64 = 1.8061, then the value of log 16 will be (approx)?

A) 1.9048 B) 1.2040
C) 0.9840 D) 1.4521
 
Answer & Explanation Answer: B) 1.2040

Explanation:

Given that, 

 

Report Error

View Answer Workspace Report Error Discuss

11 1030
Q:

A fast moving superfast express crosses another pasenger train in 20 seconds. The speed of faster train is 72 km/hr and speeds of slower train is 27 km/h. Also the length of faster ntrain is 100m, then find the length of the slower train if they are moving in the same direction.

A) 100 m B) 125 m
C) 150 m D) 175 m
 
Answer & Explanation Answer: C) 150 m

Explanation:

Report Error

View Answer Workspace Report Error Discuss

14 1083