Home page for accesible maths Math 101 Chapter 4: Taylor series and complex numbers

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4.9 Numerical values

sinx=x-x33!+x55!-.\sin x=x-{{x^{3}}\over{3!}}+{{x^{5}}\over{5!}}-\dots.

Let p3(x)=x-x3/6p_{3}(x)=x-x^{3}/6. The quality of the approximation can be judged from the following table. Here the percentage relative error is R=100|p3(x)-sinx|/sinxR=100|p_{3}(x)-\sin x|/\sin x.

x    sinx  p3(x)    Rx\qquad\qquad\sin x\qquad p_{3}(x)\qquad\quad R
0.01    0.00999980.009999800.01\qquad\quad 0.0099998\quad 0.0099998\quad 0
0.10    0.09983340.099833310-40.10\qquad\quad 0.0998334\quad 0.0998333\quad 10^{-4}
1.00    0.84147090.833333311.00\qquad\quad 0.8414709\quad 0.8333333\quad 1
2.00    0.90929740.6666667272.00\qquad\quad 0.9092974\quad 0.6666667\quad 27