cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Showing results for 
Search instead for 
Did you mean: 

Community Tip - You can subscribe to a forum, label or individual post and receive email notifications when someone posts a new topic or reply. Learn more! X

I could not find one solution with root function

Cornel
19-Tanzanite

I could not find one solution with root function

Hello,

Cornel_0-1690360996679.png

Cornel_4-1690361087312.png

Cornel_5-1690361095897.png

 

Cornel_6-1690361120831.png

Cornel_0-1690361312068.png

Cornel_8-1690361138370.png

ACCEPTED SOLUTION

Accepted Solutions
LucMeekes
23-Emerald III
(To:Cornel)

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

 

 

View solution in original post

3 REPLIES 3
LucMeekes
23-Emerald III
(To:Cornel)

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

 

 

Cornel
19-Tanzanite
(To:LucMeekes)

Ah, I see...

Cornel_0-1690365084532.png

 

Werner_E
25-Diamond I
(To:Cornel)

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

 

Announcements

Top Tags