Question on doing simple integral and using calculator

Professional Engineer & PE Exam Forum

Help Support Professional Engineer & PE Exam Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Sparky Bill PE

Senior, Master, Professional, Licensed Electrical
Joined
Jun 30, 2019
Messages
303
Reaction score
149
Location
Chattanooga TN
I can't get this answer in my calculator and I'm embarrassed but apparently I can't figure out how to do this integral either. I don't see how its simply the time multiplied to the current. 

I don't know why the current wouldn't be squared and divided by 2 when taking the integral. 

image.png

 
Found a youtube video that helped, Current is a constant so you can just pull that out, integral of just 180 is 180. 

Does anyone know how I could have solved this using calculator? 

 
I just want to point that I've taken the power PE 7 times and never once did I integrate 

 
I can't get this answer in my calculator and I'm embarrassed but apparently I can't figure out how to do this integral either. I don't see how its simply the time multiplied to the current. 

I don't know why the current wouldn't be squared and divided by 2 when taking the integral. 

View attachment 19103
without seeing the actual problem, I would just assume that my given below are correct. Is this from a particular practice problem?

You won't be able to use the integration using your calculator because the unknown is the current. You will need to manually integrate it similar to the solution.

But in my perspective, I would just use differential equation to solve the current. Much easier See my below solution:

122673714_3591973574186469_8951290629614595305_n.jpg

 
I just want to point that I've taken the power PE 7 times and never once did I integrate 
The fact that this reference handbook is only like 90 pages, and 10 are dedicated to math, I seen them incorporating questions that involve math if applicable like this. I pray I'm wrong because I earned my way through enough with the FE and math I don't want to live that life again. LOL

 
The fact that this reference handbook is only like 90 pages, and 10 are dedicated to math, I seen them incorporating questions that involve math if applicable like this. I pray I'm wrong because I earned my way through enough with the FE and math I don't want to live that life again. LOL
I have to say, there is a good amount of formulas in the NCEES reference handbook that I've never had to use in any of the practice exams I've taken so far. The majority of them are lightning-protection, for example.

...that kinda worries me, actually. Seeing a lot of formulas in the reference handbook which I've never had to use at all. If they pop up in the actual exam and I have no familiarity with these formulas, I guess I'm going to have to rely purely on this handbook for those questions...

And then there are many formulas I've used in the practice exams I have that aren't in the reference handbook...

 
I have to say, there is a good amount of formulas in the NCEES reference handbook that I've never had to use in any of the practice exams I've taken so far. The majority of them are lightning-protection, for example.

...that kinda worries me, actually. Seeing a lot of formulas in the reference handbook which I've never had to use at all. If they pop up in the actual exam and I have no familiarity with these formulas, I guess I'm going to have to rely purely on this handbook for those questions...

And then there are many formulas I've used in the practice exams I have that aren't in the reference handbook...
Yeah I will seriously need a trigger warning if its just BAM "solve this differential equation" or "Solve this integral using substitution method" GOD NO GOD NO

 
Back
Top