23 Maths -- Numerical Computations

Using bisection method, find the root of the equation f(x)=x2 -6logx-3=0(2<=x<=3)'correct to 4 decimal places with an accuracy of 10 -2 .

Using bisection method, find the root of the equation f(x)=x2 -6logx-3=0(2<=x<=3)'correct to 4 decimal places with an accuracy of 10 -2 .

Here,  f(x)=x2 -6 logx-3=0

f(2)=4-6 log2-3=-0.806

f(3)=9-6 log3-3=3.1373

f(2).f(3)=-0.806*3.1373=-2.529422 which is negative.

Hence, the root lies between 2 and 3

c0 =(2+3)/2=2.5

f(2.5)=6.25-6 log 2.5-3=0.8623

Now

n
a(-ve)
b(+ve)
cn
f(cn)
0
2
3
2.5
0.8623
1
2
2.5
2.25
-0.050595
2
2.25
2.5
2.375
0.38664
3
2.25
2.375
2.3125
0.1631658
4
2.25
2.3125
2.28125
0.05506
5
2.25
2.28125
2.265625
0.001925

From the table,

f(2.265625)=0.001928<10-2 

Therefore, the root of the given equation correct upto four paces of decimal=2.2656

Here,  f(x)=x2 -6 logx-3=0

f(2)=4-6 log2-3=-0.806

f(3)=9-6 log3-3=3.1373

f(2).f(3)=-0.806*3.1373=-2.529422 which is negative.

Hence, the root lies between 2 and 3

c0 =(2+3)/2=2.5

f(2.5)=6.25-6 log 2.5-3=0.8623

Now

n
a(-ve)
b(+ve)
cn
f(cn)
0
2
3
2.5
0.8623
1
2
2.5
2.25
-0.050595
2
2.25
2.5
2.375
0.38664
3
2.25
2.375
2.3125
0.1631658
4
2.25
2.3125
2.28125
0.05506
5
2.25
2.28125
2.265625
0.001925

From the table,

f(2.265625)=0.001928<10-2 

Therefore, the root of the given equation correct upto four paces of decimal=2.2656

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