Plus42 Equations, Preview Release

[Vincent Weber]

(11-30-2021 03:11 PM)Albert Chan Wrote:  Is this a feature, or a bug ?

emu71b:
>FNROOT(0,3,1+(1-SIN(FX))^3)
 1.54979993037
>FVALUE ! minimum = 1 + 0 = 1
 1.00000000001

Plus42:
eqn = "1 + (1-SIN(X))^3", go in "CALC", 0 "X" 3 "X", "X" (to solve)

375.E-3 - i831.E-3 // complex solution ?

In the real domain, SIN(X) is always ≤=1, -SIN(X) ≥ -1, 1-SIN(X)≥0, and (1-SIN(X))^3≥0, so the equation result is always ≥1, and therefore never equal to 0. How on earth can the HP-71B find a real root to this ??