HP Prime Calculator: Basic Usage

[blixel]

This is my first graphing calculaot, so forgive me ignorance please.

When I go to the CAS menu and I want to immediately simplify an equation or expression, how do I get the simplify() up on the screen? (The only way I can get it to work is to first press a number like 1 in order to activate the cursor in the box, and then hit backspace, and then press the simplif button.)

How do I type a SINGLE opening parenthesis, or a SINGLE closing parenthesis without having to use () and then deleting the extra parenthesis I don't want? As an overly simplified example, if I type 2+2 and then decide to go back and put 2+2 in parenthesis. I have to go to the beginning, press (), then delete the extra ), then go to the end and press (), and delete the extra (.

How do I evaluate simple equations like 8x=16 so that x=2? Right now, when I press 8 ALPHA (times) x, SHIFT (period) =, 2 and press enter. It just rewrites 8*x=2 on the screen. I expect a x=2 as an answer.

How do I simplify (c^3d^5)^2 * (cd^3)^3 so that it gives me the right answer as opposed to re-writing the expression and then giving me the wrong answer? (Right answer: c^9d^19)

How do I make the proot() function return accurate values? For example, proot(2y^2 + 7y + 6) should return positive 3 and positive 4, not -2 and -1.5.

[Joe_Horn · Accepted solution]

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When I go to the CAS menu and I want to immediately simplify an equation or expression, how do I get the simplify() up on the screen? (The only way I can get it to work is to first press a number like 1 in order to activate the cursor in the box, and then hit backspace, and then press the simplif button.) 

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The trick is to press the space key first.  However, it's usually a better idea to just type the expression first, press Enter, and then press simplify.  That way the original unmodified expression is in the history so that you can tap it and re-use it.

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How do I type a SINGLE opening parenthesis, or a SINGLE closing parenthesis without having to use () and then deleting the extra parenthesis I don't want? As an overly simplified example, if I type 2+2 and then decide to go back and put 2+2 in parenthesis. I have to go to the beginning, press (), then delete the extra ), then go to the end and press (), and delete the extra (.

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Method 1: Shift Vars (Chars), then tap the parenthesis that you want.

Method 2: () Shift backspace, for a left parenthesis;  () backspace right-cursor, for a right parenthesis.

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How do I evaluate simple equations like 8x=16 so that x=2? Right now, when I press 8 ALPHA (times) x, SHIFT (period) =, 2 and press enter. It just rewrites 8*x=2 on the screen. I expect a x=2 as an answer.

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Type this: solve(8*x=16)

Suggestion: press Toolbox, the CAS tab, Solve, then explore that menu by highlighting one of the Solve funstions and then press the Help key.  There are many powerful options there.

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How do I simplify (c^3d^5)^2 * (cd^3)^3 so that it gives me the right answer as opposed to re-writing the expression and then giving me the wrong answer? (Right answer: c^9d^19)

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First, avoid "implied multiplication".  Since variables can have more than one letter, the Prime can't know that you mean c*d when you type cd.  It thinks you mean a variable called "cd".

Your example should be typed as (c^3*d^5)^2 * (c*d^3)^3.  Prime correctly simplifies that.

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How do I make the proot() function return accurate values? For example, proot(2y^2 + 7y + 6) should return positive 3 and positive 4, not -2 and -1.5.

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Your example solves 2y^2+7y+6=0.  Prime's solutions are correct:

2*(-1.5)^2 +7*(-1.5) +6 = 0

2*(-2)^2 +7*(-2) +6 = 0

2*3^2 +7*3 +6 = 45

2*4^2 +7*4 +6 = 66

Another approach: factor(2y^2+7y+6).  Prime returns (y+2)*(2*x+3).  As you can see, setting each factor equal to zero yields the solutions that Prime gave above (-1.5 and -2).

Hope that helps!

[blixel]

Thanks for the great reply. Very helpful.

@Joe_Horn wrote:

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The trick is to press the space key first.  However, it's usually a better idea to just type the expression first, press Enter, and then press simplify.  That way the original unmodified expression is in the history so that you can tap it and re-use it.

Ok, so that's the same thing I was already doing. Press a key, then press back space. Hmm... seems like there should be a way to make the box active without having to press unecessary keys.

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Method 1: Shift Vars (Chars), then tap the parenthesis that you want.

Method 2: () Shift backspace, for a left parenthesis;  () backspace right-cursor, for a right parenthesis.

In other words, no.  🙂  Pressing extra keys unecessarily is still required.

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Type this: solve(8*x=16)

Suggestion: press Toolbox, the CAS tab, Solve, then explore that menu by highlighting one of the Solve funstions and then press the Help key.  There are many powerful options there.

Thanks.

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How do I simplify (c^3d^5)^2 * (cd^3)^3 so that it gives me the right answer as opposed to re-writing the expression and then giving me the wrong answer? (Right answer: c^9d^19)

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First, avoid "implied multiplication".  Since variables can have more than one letter, the Prime can't know that you mean c*d when you type cd.  It thinks you mean a variable called "cd".

Your example should be typed as (c^3*d^5)^2 * (c*d^3)^3.  Prime correctly simplifies that.

Is there a way to make the answer display with normal algebra output? All the extra multiplication symbols is very confusing. When comparing what I see in a textbook to what I see on the calculator, it's hard to tell whether or not I'm looking at the same answer due to all the extra symbols on the calculator.

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How do I make the proot() function return accurate values? For example, proot(2y^2 + 7y + 6) should return positive 3 and positive 4, not -2 and -1.5.

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Your example solves 2y^2+7y+6=0.  Prime's solutions are correct:

2*(-1.5)^2 +7*(-1.5) +6 = 0

2*(-2)^2 +7*(-2) +6 = 0

2*3^2 +7*3 +6 = 45

2*4^2 +7*4 +6 = 66

Another approach: factor(2y^2+7y+6).  Prime returns (y+2)*(2*x+3).  As you can see, setting each factor equal to zero yields the solutions that Prime gave above (-1.5 and -2).

I misunderstood what that function was doing. I thought it was helping me find my pair of numbers that would multiply together to equal A*C, and add up together to equal B. Does the calculator have that function?

Also, if I'm given 3x + y = -12 and I need to find the x and y-intercept, how do I do that on the calculator?

Also, if I have 2x - 5y = 4 and I need to find the slope-intercept form, can I input 2x - 5y = 4 into the calculator and have it return y = 2/5x - 4/5?

Why does the calculator differentiate between x^2 (when you press the x-squared button) and x^2 (when you press the x-to the power of button). For example, type x, then press the x-squared button, then press x and raised to the power of 3 and hit enter. You will get an error. But if you press x, then press to the power of 2, and then press x, and then press to the power of 3, you will get x to the power of 5 as your answer. What is wrong with the x-squared button? It only seems to work if you don't have any other exponents in the expression.

[Joe_Horn]

I wrote: The trick is to press the space key first.  ...

You wrote: Ok, so that's the same thing I was already doing. Press a key, then press back space. Hmm... seems like there should be a way to make the box active without having to press unecessary keys.

Answer: There is a way: Just press the space key, then keep typing.  No need to backspace the space character. 

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You wrote: Is there a way to make the answer display with normal algebra output? All the extra multiplication symbols is very confusing. When comparing what I see in a textbook to what I see on the calculator, it's hard to tell whether or not I'm looking at the same answer due to all the extra symbols on the calculator.

Answer: No, because of the ambiguity I mentioned above.  In books, the variables are already known, so there is no ambiguity.  Prime cannot read minds, however, so you have to tell it what you are thinking. 

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You wrote: I misunderstood what that function was doing. I thought it was helping me find my pair of numbers that would multiply together to equal A*C, and add up together to equal B. Does the calculator have that function?

Answer: Here's one way to get what you're looking for. Just find the roots of the quadratic, convert them to fractions (by pressing the a b/c key if necessary), then multiply them by the lowest common denominator.  The numbers you're looking for will be the negative of what you see.  This only works if the numbers you're looking for are integers with no common factors; otherwise, what you multiply by will have to be adjusted.

Example:

solve(2*x^2 +7*x +6) Enter

*2 Enter --> {-4, -3}

... so the numbers you're looking for are 4 and 3.

There's probably a simpler way to do this.  Hopefully somebody will post it here.

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You wrote: Also, if I'm given 3x + y = -12 and I need to find the x and y-intercept, how do I do that on the calculator?

Answer: Just solve for y.  Example: solve(3*x+y=-12, y) yields -3*x-12.  Since y=mx+b, the slope is -3 and the y-intercept is -12.  The x-intercept is what x is equal to when y is zero, so substitute 0 for y, which turns the original equation into 3x=-12.  solve(3*x=-12) --> -4, the x-intercept.

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You wrote: Also, if I have 2x - 5y = 4 and I need to find the slope-intercept form, can I input 2x - 5y = 4 into the calculator and have it return y = 2/5x - 4/5?

Answer: Yes.  Just solve for the variable that you want to isolate on the left side of your equation, as we saw above.

Your example:

solve(2*x -5*y =4, y) Enter

simplify --> (2x-4)/5, obviously equal to 2x/5 - 4/5.

Sorry about the formatting here... I can't figure out this forum's strange editor.

By the way, HP has a forum dedicated to their calculators: http://h30499.www3.hp.com/t5/Calculators/bd-p/bsc-408

Disclaimer: I don't work for HP.  I'm just another happy HP customer.