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Best answer by LucMeekes

The bracketed root function requires opposite signs of the function value at the interval ends. Your problem is the same as:

LucMeekes_0-1690364915461.pngLucMeekes_1-1690364921876.png

LucMeekes_2-1690364930021.png

But, guess:

LucMeekes_3-1690364950828.png

then:

LucMeekes_4-1690364968774.png

(comes close).

In Mathcad:

LucMeekes_5-1690365477467.png

 

Success!
Luc

 

 

2 replies

L
LucMeekes23-Emerald IVAnswer
23-Emerald IV
July 26, 2023

The bracketed root function requires opposite signs of the function value at the interval ends. Your problem is the same as:

LucMeekes_0-1690364915461.pngLucMeekes_1-1690364921876.png

LucMeekes_2-1690364930021.png

But, guess:

LucMeekes_3-1690364950828.png

then:

LucMeekes_4-1690364968774.png

(comes close).

In Mathcad:

LucMeekes_5-1690365477467.png

 

Success!
Luc

 

 

C
Cornel19-TanzaniteAuthor
19-Tanzanite
July 26, 2023

Ah, I see...

Cornel_0-1690365084532.png

 

W
Werner_E25-Diamond I
25-Diamond I
July 26, 2023

Read the error message carefully!

The function root() when given an interval finds only zeros where the curve crosses the x-axis, but not those where, as in your case, the curve only touches the x-axis. Therefore it is also required (see error message) that the function values at the interval boundaries must have different signs.
You could try the root() function without interval specification but with a guess value.

Werner_E_0-1690366012019.png

In your case the equation is quite simple and can be solved exactly.

Primes "new" symbolic unfortunately is not very capable in terms of user friendliness as it gives us

Werner_E_1-1690366466510.png

 

Compare this with the result of the old symbolic engine (muPad) in Prime 6

Werner_E_2-1690366515973.png

 

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