cancel
Showing results for 
Search instead for 
Did you mean: 
Willempy
New member
2 1 0 0
Message 1 of 4
407
Flag Post

Integration failue of int(tan(x)^*cos(x)^3dx

HP Recommended
HP Prime

Good day everyone,

 

I am currently doing a math course, and one of the exercises was integrate the following: tan(x)^2*cos(x)^3. Solving this by hand returns sin(x)^3/3. Entering this on the HP Prime returns -sin(x).This does not seem correct to me. I have verified the answer with maple and a TI-Nspire, both return the correct answer.

 

Any ideas on this issue?

 

Kind regards.

0 Kudos
Tags (1)
3 REPLIES 3
Maké
Level 9
3,551 3,490 180 541
Message 2 of 4
Flag Post
HP Recommended

Hi!, @Willempy :

You must see, the images for Configure and Solve ...

CAS_1.PNG CAS_2.PNG 

Now, if you needed simplify, the result, is ...

CAS_3.PNG

Note : Conceptually, the tangent of an angle is equal to the sine divided by the cosine of that angle. If you put it that way, you'll get the result you've indicated.

Kind Regards !.
Have a nice day !.
@Maké (Technical Advisor Premium - HP Program Top Contributor).
Provost in HP Spanish Public Forum ... https://h30467.www3.hp.com/
0 Kudos
Maké
Level 9
3,551 3,490 180 541
Message 3 of 4
Flag Post
HP Recommended

Hi!, @Willempy :

Too, you can solve indefinite integrate step by step and next time apply "u" substitution, from ... https://www.symbolab.com/solver/integral-calculator/%5Cint%20tan%5Cleft(x%5Cright)%5E%7B2%7D%5Ccdot%...

Kind Regards !.
Have a nice day !.
@Maké (Technical Advisor Premium - HP Program Top Contributor).
Provost in HP Spanish Public Forum ... https://h30467.www3.hp.com/
Willempy
Author
New member
2 1 0 0
Message 4 of 4
Flag Post
HP Recommended

Hey Maké,

 

Thanks for the clear explanation. I was able to get the correct result by hand. Indeed, when I enter tan(x) as sin(x)/cos(x) in the HP prime, the returned answer is correct. Somehow the HP prime seems to have trouble integrating tan(x) and its exponents. I will find out how and where to file a bug report.

 

Kind regards,

 

Willempy

0 Kudos
† The opinions expressed above are the personal opinions of the authors, not of HP. By using this site, you accept the Terms of Use and Rules of Participation