pre-cal

What are the steps for solving this?

Directions Use the quadratic formula to solve the equation in the interval [0,2PI). Then use a graphing utility to approximate the angle x.

4cos^2x-4cosx-1=0

thanks.

1. 👍 0
2. 👎 0
3. 👁 177

cosx= (4+-sqrt(16+4))/8

graph y=4cos^2 x - 4cosx + 1 and note where it crosses the y=0 axis.

1. 👍 0
2. 👎 0

Similar Questions

1. Math

Use the quadratic formula to solve each of the following quadratic equations... 1. 2x^2-5x=3 2. 3x^2-2x+1=0 Rearrange the equation in quadratic formula form. 2x^2 -5x -3 = 0 Then use the formula. Tell me what you don't understand

asked by Tomika on June 13, 2007
2. Algebra

I was given this answers to a problems I solved but I do not understand what she means hope you can help. Before attempting to solve this quadratic equation, determine how many solutions there will be for this quadratic equation.

asked by Charly on June 2, 2011
3. Algebra

I was given this answers to a problems I solved but I do not understand what she means hope you can help. Before attempting to solve this quadratic equation, determine how many solutions there will be for this quadratic equation.

asked by Charly on June 2, 2011
4. 8th Grade Algebra

You know how to solve quadratic equations using algebra, graphs and the quadratic formula. Sometimes one method of solving is more convenient than another method. Describe how you would solve each equation. Give reasons for you

asked by Joy on March 30, 2009
5. Algebra

I am still having trouble solving this problem. Use the quadratic formula to solve this equation: 4k(k+13)=13

asked by Jay on April 26, 2012
6. Algebra

How do I solve a quadratic equation x^2 - x = 30 by completing the square- I don't understand-could someone just explain the steps to solving this

asked by Jamie on September 21, 2010
7. algebra

2x^2-2x-1=0 How do I use the quadratic formula to solve this because I am totally new at this and need help? Please show me the steps for this equation,so I will be able to do it own my own. Thank you.

asked by paulina on September 5, 2010
8. algebra II

I'm quite clueless as to how to solve this. I know the quadratic equation but am not sure how to get this equation into the format to plug in to the quadratic... Solve the quadratic equation using the formula

asked by maddie on May 24, 2009
9. College Math II

Solve by using the quadratic formula. x^2 + 6x + 6 = 0 I am having problems using the quadratic formula to get the right answer. Can someone show me the steps that I use? Thanks.

asked by Lori on November 21, 2009
10. math

(4.35E-2 - x)(7.56E-2 -x ) ============================ (0.324 + 2x)2 Rearrange to get an expression of the form ax2 + bx + c = 0 and use the quadratic formula (solve for x. This gives: x = 1.05E-2, 0.143 basically i understand

asked by bob on March 10, 2012

More Similar Questions