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Question: Why do I get a wrong evaluation result after simplification

Question:Why do I get a wrong evaluation result after simplification

silverberry 10 Maple
numeric simplification
March 29 2022
2

After simplifying an expression, I get different numerical results. The first one (9717.251005) should be correct. The simplification also seems correct.

Why do I get a wrong evaluation result after simplification? Is this a numerical problem?

I'm using Maple 2021 and this my code:

restart

values := {m = 1400, d = 1/2 * 1.225*0.74, xpr = 27+7/9, A = -94.25, B = 4096, C = -2699, D = 131947, u0 = 0.1, P_max = 9705, u = 0.5}

Pa_R := ((((A*D - B*C)*(sqrt(4*A^2*d*u*xpr^2 + 4*A*d*(A*D - B*C)*xpr + (A*D - B*C)^2) + (2*d*xpr + D)*A - C*B))/(2*A^2*d) + u*xpr^2)*(-A*D + C*B - sqrt(4*A^2*d*u*xpr^2 + 4*A*d*(A*D - B*C)*xpr + (A*D - B*C)^2)))/(2*A*d)

Pa_R2 := simplify(Pa_R)

eval(Pa_R, values)

eval(Pa_R2, values)

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