Integral in solve

[lrdheat]

How would I set up an integral in solve app to, say, have integral x^2 from 0 to y = 20?

[Joe Horn]

(07-13-2014 06:05 PM)lrdheat Wrote:  How would I set up an integral in solve app to, say, have integral x^2 from 0 to y = 20?

Do you mean \(\int_0^{20}x^{2} dx\) ? That's not an equation, it's just an expression. To evaluate an expression, just type it into Home or CAS; this one evaluates to 8000/3. The Solve app is for solving equations.

If I misunderstood your question, what equation you want to solve?

[eried]

(07-14-2014 08:17 AM)Joe Horn Wrote:  

(07-13-2014 06:05 PM)lrdheat Wrote:  How would I set up an integral in solve app to, say, have integral x^2 from 0 to y = 20?

Do you mean \(\int_0^{20}x^{2} dx\) ? That's not an equation, it's just an expression. To evaluate an expression, just type it into Home or CAS; this one evaluates to 8000/3. The Solve app is for solving equations.

If I misunderstood your question, what equation you want to solve?

He says equals to 20, so it is an equation. Not solvable in the solver.

[CR Haeger]

(07-13-2014 06:05 PM)lrdheat Wrote:  How would I set up an integral in solve app to, say, have integral x^2 from 0 to y = 20?

In Solve App this seems to work okay (using Home variables X, T and the math template):
   

In CAS, you can use solve(), fsolve() to get a numerical or symbolic result
   

[Tim Wessman]

(07-13-2014 06:05 PM)lrdheat Wrote:  How would I set up an integral in solve app to, say, have integral x^2 from 0 to y = 20?

This works fine. However, if you tried this and it didn't work, it is probably because you accidentally did x^2d(x=20) instead of (x^2)dx =20

Make sure you press the right arrow once after to move out of the variable of integration template location before your =20.

[Anderson Costa]

(07-13-2014 06:05 PM)lrdheat Wrote:  How would I set up an integral in solve app to, say, have integral x^2 from 0 to y = 20?

It may be expressed for int(x^2,x,0,y)=20...
It's an Integral equation and is easily solved in Solve App!

[lrdheat]

I've tried the syntax (and other variations) suggested by Anderson, Tim, and CR. In each case, when I go into Num template and submit a guess, I get "bad guess(es)". Could I be in an odd operating mode?

[eried]

(07-15-2014 02:09 AM)lrdheat Wrote:  I've tried the syntax (and other variations) suggested by Anderson, Tim, and CR. In each case, when I go into Num template and submit a guess, I get "bad guess(es)". Could I be in an odd operating mode?

I get the same :/ that's why I said it was not solvable in that app. I tried with int and with the template too.

[Joe Horn]

(07-15-2014 02:48 AM)eried Wrote:  

(07-15-2014 02:09 AM)lrdheat Wrote:  I've tried the syntax (and other variations) suggested by Anderson, Tim, and CR. In each case, when I go into Num template and submit a guess, I get "bad guess(es)". Could I be in an odd operating mode?

I get the same :/ that's why I said it was not solvable in that app. I tried with int and with the template too.

See Tim's reply above. If you're using Textbook Entry mode, you have to press right-cursor between typing dX and typing =20.