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Greenhorn
Posts: 7
Hi! I am really new to JAVA and am trying to figure out how to make it work.
I am trying to write a basic java program for a quadratic equation where b2 – 4ac is the discriminant being tested for.
I would like the program to prompt the user to enter values for a, b, and c and displays the result based on the discriminant.  I’m trying to make it so that if the discriminant is positive, two roots will be displayed, and if the discriminant is 0, one root is displayed.  Otherwise, I want it to display “The equation has no real roots”.
I heard that using Math.pow(x, 0.5) to compute the square root of x would work the best.
Would very much appreciate some examples or help!

Thank you!

Bartender
Posts: 1773
45
Let me understand correctly, if user enters : a=2, b=3, c=4, your program would do

(3 * 3)– (4 *2 *4 ) = -23

And your output will be "The equation has no real roots" since its negative 23.

I would break your code into 3 parts:
1. Taking entry from user for a,b,c
2. Calculating equation result.
3. Giving an output based on the result

Which part are you stuck at ?
What have you done so far ?

Hint, You can use Math.sqrt() for the square root.

Zachary Kang
Greenhorn
Posts: 7
I have not done any of it yet, for I am trying to understand how I would go about starting this.  What is the notation?  How would I write something like this?

Rancher
Posts: 2862
32
Start by looking at the methods in the Math class to see what is available.

salvin francis
Bartender
Posts: 1773
45

Zachary Kang wrote:I have not done any of it yet, for I am trying to understand how I would go about starting this.  What is the notation?  How would I write something like this?

Hi Zachary Kang,
Are you aware of the following ?
• Writing a program that simply prints "Hello world"
• Using variables in your code
• Doing calculations on one variable and assigning the result to another
• Using classes
• Using methods

• You may have to look at the java tutorials here: https://docs.oracle.com/javase/tutorial/ to learn the basics of Java.
Keep us updated on your progress and we can help you out if you are stuck.