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Use the Newton’s method to approximate the solution of the equation: 1-x-tan x = 0 starting at x0 = 0.5 (the initial value). i.e. Find x1,x2,x3.. .

 Oct 28, 2014

Best Answer 

 #1
avatar+118703 
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Newton's method

You are probably supposed to know the formula but I can't remember formulas so I work it out ever time.

$Remember,thegradientofthetangentat$x=x1$isgivenby$f(x0)sof(x0)=f(x0)0x0x1f(x0)=f(x0)x0x1x0x1=f(x0)f(x0)x1=x0+f(x0)f(x0)x1=x0f(x0)f(x0)$Nowyouhavetheformula$x1=x0f(x0)f(x0)

 

1-x-tan x = 0 starting at x0 = 0.5 

Let

f(x)=1xtanxf(x)=1sec2xf(0.5)=10.5tan0.5f(0.5)=0.50.546f(0.5)=0.046f(0.5)=1sec2(0.5)f(0.5)=1(1/cos2(0.5))f(0.5)=2.298sox1=0.5f(0.5)f(0.5)x1=0.50.0462.298x1=0.480

 

I have applied newtons method just once.

If you want more accuracy you can apply it again and again until you are happy. :)

 Oct 28, 2014
 #1
avatar+118703 
+5
Best Answer

Newton's method

You are probably supposed to know the formula but I can't remember formulas so I work it out ever time.

$Remember,thegradientofthetangentat$x=x1$isgivenby$f(x0)sof(x0)=f(x0)0x0x1f(x0)=f(x0)x0x1x0x1=f(x0)f(x0)x1=x0+f(x0)f(x0)x1=x0f(x0)f(x0)$Nowyouhavetheformula$x1=x0f(x0)f(x0)

 

1-x-tan x = 0 starting at x0 = 0.5 

Let

f(x)=1xtanxf(x)=1sec2xf(0.5)=10.5tan0.5f(0.5)=0.50.546f(0.5)=0.046f(0.5)=1sec2(0.5)f(0.5)=1(1/cos2(0.5))f(0.5)=2.298sox1=0.5f(0.5)f(0.5)x1=0.50.0462.298x1=0.480

 

I have applied newtons method just once.

If you want more accuracy you can apply it again and again until you are happy. :)

Melody Oct 28, 2014

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