Mathematics Q.1

Let ( a , b ) (a,b) be the outcome of throwing a pair of fair dice. What is the probability for which lim x 0 ln ( ( cos ( x ) ) a ) x b \lim_{ x\rightarrow 0 }\frac { { \ln { \left( { \left( \cos { \left( x \right) } \right) }^{ a } \right) } } }{ { x }^{ b } } exists and is finite?

  • Answer upto 3 Decimal Places.


The answer is 0.3333333333333333333333333.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

l i m x 0 ln ( ( cos ( x ) ) a ) x b = l i m x 0 a ln ( ( cos ( x ) ) ) x b lim_{ x\rightarrow 0 }\frac { { \ln { \left( { \left( \cos { \left( x \right) } \right) }^{ a } \right) } } }{ { x }^{ b } } \\ =lim_{ x\rightarrow 0 }\frac { { a\ln { \left( { \left( \cos { \left( x \right) } \right) } \right) } } }{ { x }^{ b } } \\

Let us Now Apply L'Hôpital's Rule

l i m x 0 a tan ( x ) b x b 1 = l i m x 0 tan ( x ) x a b 1 x b 2 lim_{ x\rightarrow 0 }\frac { { -a\tan { (x) } } }{ { bx }^{ b-1 } } \\ =lim_{ x\rightarrow 0 }\frac { { \tan { (x) } } }{ { x } } \frac { -a }{ b } \frac { 1 }{ { x }^{ b-2 } }

= l i m x 0 a b 1 x b 2 =lim_{ x\rightarrow 0 }\frac { -a }{ b } \frac { 1 }{ { x }^{ b-2 } }

Now for Limit to be Finite

b 2 = { 0 , 1 , 2 , 3 , 4...... } b = { 2 , 1 , 0 , 1 , 2 , 3...... } b-2=\left\{ 0,-1,-2,-3,-4...... \right\} \\ b=\left\{ 2,1,0,-1,-2,-3...... \right\} \\ \\

But b can Only be b = { 2 , 1 } b=\left\{ 2,1 \right\} as it is an outcome of a Dice.

Now probability is P = N o o f w a s t o s e l e c t " a " T o t a l N o o f w a s t o s e l e c t " a " . N o o f w a s t o s e l e c t " b " T o t a l N o o f w a s t o s e l e c t " b " P = 6 6 2 6 = 1 3 = 0.33333333333333333333 \\ \\ P=\frac { No\quad of\quad was\quad to\quad select\quad "a" }{ Total\quad No\quad of\quad was\quad to\quad select\quad "a" } .\frac { No\quad of\quad was\quad to\quad select\quad "b" }{ Total\quad No\quad of\quad was\quad to\quad select\quad "b" } \\ P=\frac { 6 }{ 6 } \frac { 2 }{ 6 } =\frac { 1 }{ 3 } =0.33333333333333333333

Moderator note:

Simple standard approach.

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...