= 1+√52
It's the Fibonacci sequence! The geometric difference between the numbers is asymptotic to the above: 1/1, 2/1, 3/2, 5/3, 8/5, etc. To get the next number in the series, simply take the sum of the previous 2.
Interesting :)
Let
y=x+1x+1x+1x+....soy=x+1yx=y−y−1dxdy=1+y−2dx=(1+y−2)dywhenx=0y=1yy2=1y=±1this is a stumbling block, I only want one valuewhenx=11=y−y−1y=y2−1y2−y−1=0y=1±√52two answers again :(
∫10x+1x+1x+1x+....dx=∫??y(1+y−2)dy=∫??y+y−1dy=[y22+lny]??
Now I have to think about those questions marks
To be continued :)
I can see Heureka's answer underneath ..... I'll have to think about it more but I will leave this here for now.
Maybe Heuarka, you might like to commnent on what I have done ??
You cannot find the log of a negative number so I am goinf for the positive values.( this is not great mathematical reasoning here:
I'd believe Heureka if I were you LOL
∫10x+1x+1x+1x+....dx=∫1+√521y(1+y−2)dy=∫1+√521y+y−1dy=[y22+lny]1+√521=[(1+√52)2÷2+ln(1+√52)−12]=[(1+√5)28+ln(1+√52)−48]=[6+2√5−48+ln(1+√52)]=[2+2√58+ln(1+√52)]=1+√54+ln(1+√52)
Oh dear, these two regions are not the same area. What a pity.
I guess I better keep thinking!
Ok. I think i got this-
Lets call the expression f(x). we know that x+1/f(x)=f(x). We can multiply by f(x) and get-
x*f(x)+1=f(x)2 | subtract x*f(x)
f(x)2-x*f(x)=1 | add x2/4
(f(x)-x/2)2=1+x2/4
f(x)=x/2+(1+x2/4)1/2.
Im terrible at finding integrals, so i used an integral calculator:
its integral is:
1/4 (x (sqrt(x^2 + 4) + x) + 4 sinh^(-1)(x/2)) + constant
One more :)
Continuous Fraction.
sum=x+1x+1x+1x+⋯sum=x+1sumsum−1sum=xsum2−1sum=xsum2−1=x⋅sumsum2−x⋅sum−1=0sum=x±√x2−4⋅(−1)2sum=x±√x2+42
1∫x=0x+1x+1x+1x+⋯ dx=1∫x=0sum dx=1∫x=0x±√x2+42 dx=121∫x=0x dx±1∫x=0√x2+42 dx=12[x22]1x=0±1∫x=02⋅√(x2)2+12 dx=14±1∫x=0√(x2)2+1 dxsubstitute: x2=sinh(z)z=arsinh(x2)dx=2⋅cosh(z) dz new limits: x=0:z=arsinh(02)⇒z=0x=1:z=arsinh(12) =14±arsinh(12)∫x=0√sinh2(z)+1⋅2⋅cosh(z) dz cosh2(z)=1+sinh2(z) =14±arsinh(12)∫x=0√cosh2(z)⋅2⋅cosh(z) dz=14±arsinh(12)∫x=0cosh(z)⋅2⋅cosh(z) dz=14±2arsinh(12)∫x=0cosh2(z) dz cosh2(z)=12+12cosh(2z) =14±2arsinh(12)∫x=012+12cosh(2z) dz=14±arsinh(12)∫x=01+cosh(2z) dz=14±(arsinh(12)∫x=0 dz+arsinh(12)∫x=0cosh(2z) dz)=14±([z]arsinh(12)x=0+[sinh(2z)2]arsinh(12)x=0) sinh(2z)=2sinh(z)cosh(z) =14±([z]arsinh(12)x=0+[2sinh(z)cosh(z)2]arsinh(12)x=0)=14±([z]arsinh(12)x=0+[sinh(z)cosh(z)]arsinh(12)x=0)=14±(arsinh(12)+12⋅cosh(arsinh(12)))=14±(0.4812118250596+12⋅cosh(0.4812118250596))=14±(1.0402288194345508)
=14+1.0402288194345508or=14−1.0402288194345508=1.2902288194345508or=−0.7902288194345508