Here, y is a function of x satisfying the equation xy″+ay′+(x–b)y=0, where a and b are integers.xy0.81.7303611.955321.22.197561.42.456931.62.733091.83.0254922.33332.23.65563
Now, Δnf(x0)=x1−x0Δn−1f(x1)−Δn−1f(x0)and, Δf(x0)=x1−x0f(x1)−f(x0),Δf(x1)=x2−x1f(x2)−f(x1)∴Δf(x0)=1.1248Δ2f(x0)=0.216Δ3f(x0)=−0.003125Δ4f(x0)=−0.00494792Δ5f(x0)=−0.000520833Δ6f(x0)=−21.7025Δ7f(x0)=108.512
So,
f(x)=108.512(x−2)(x−1.8)(x−1.6)(x−1.4)(x−1.2)(x−1)(x−0.8)−21.7025(x−1.8)(x−1.6)(x−1.4)(x−1.2)(x−1)(x−0.8)−0.000520833(x−1.6)(x−1.4)(x−1.2)(x−1)(x−0.8)−0.00494792(x−1.4)(x−1.2)(x−1)(x−0.8)−0.003125(x−1.2)(x−1)(x−0.8)+0.216(x−1)(x−0.8)+1.1248(x−0.8)+1.73036=108.512x7−1085.12x6+4574.87x5−10538.7x4+14321.7x3−11477.1x2+5020.82x−923.044
Now, y′=f′(x)=759.512x6−6510.72x5+22874.35x4−42154.8x3+42965.1x2−22954.2x+5020.82y′′=f′′(x)=4557.12x5−32553.6x4+91497.4x3−126464.4x2+85930.2x−22954.2
We have , xy″+ay′+(x–b)y=0
Putting x=1,y′(1)=0.168y′′(1)=12.9329∴0.168a−1.95532b+14.88822=0 (1)Putting x=0.8,y′(0.8)=6.9152y′′(0.8)=−141.1029∴6.9152a−1.73036b=111.15196 (2)
Solving (1)and (2),
We get a=8,b=6
So, a=8,b=6a=8,b=6
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