Thread: Solving a Trig equation by graph

I need to use the graphing calculator to approximate, to three decimal places,for the solutions to the homework problems I am working on, giving all the solutions possible.
Here are two of the even ones in the book.
cos(x)=2x^2
x=?

cos(x)=x^2/2
x=?

I would appreciate an example of any method to use so I can grasp this and finish my homework, so I can study for another class. This website is such a help, we are very fortunate to have a site like this to help us better understand the concepts we are being taught.
Thank you very much!!
Keith Stevens

Hello, Keith!

Use a graphing calculator to approximate the solutions to three decimal places.

Try graphing and

. . and locate their intersections.

Originally Posted by kcsteven

I need to use the graphing calculator to approximate...

Hello,

which calculator do you use?

Originally Posted by kcsteven

...
Here are two of the even ones in the book.
cos(x)=2x^2
x=?

...

1. Draw the graphs of

on your calculator.
2. Place the cursor on the intercept of both graphs.
3. You get indicated the x-value and the y-value of the intercept somewhere on the screen.
4. Use the zoom-in function of your calculator, until you've got the result as exact as you need it.

5. First attempt: A(-0.63, 0.81), B(0.63, 0.81)

EB