Solving for Theta in 2bcosθ=2sinθ-1 Quadratic Equation

  • Thread starter Vitani11
  • Start date
  • Tags
    Theta
In summary, the problem involves an equation 2bcosθ=2sinθ-1 where b is a constant. The attempt at a solution included squaring both sides, foiling, and changing cosθ2 to 1-sin2θ, leading to a quadratic in sinθ. The person initially did not see the quadratic, but eventually solved it.
  • #1
Vitani11
275
3

Homework Statement


2bcosθ=2sinθ-1 where b is a constant

Homework Equations

The Attempt at a Solution


I squared both sides, foiled, and changed the cosθ2 to a 1-sin2θ. Was told I need to solve a quadratic for sine? I don't see it.
 
Physics news on Phys.org
  • #2
Vitani11 said:

Homework Statement


2bcosθ=2sinθ-1 where b is a constant

Homework Equations

The Attempt at a Solution


I squared both sides, foiled, and changed the cosθ2 to a 1-sin2θ. Was told I need to solve a quadratic for sine? I don't see it.

How can you not end up with a quadratic in ##\sin \theta##?
 
  • #3
Awesome, got it. Thanks!
 

1. What is the basic method for solving for theta in this equation?

To solve for theta in this equation, we can use the quadratic formula: (-b ± √(b^2-4ac)) / 2a, where a=2b, b=-2sinθ, and c=-1. We can then use the values of a, b, and c to plug into the formula and solve for theta.

2. How do I know which value to choose for theta?

After solving for theta using the quadratic formula, you will get two values. You can use a calculator to find the approximate value of theta, or you can graph the equation to see where it intersects with the x-axis. The value of theta where the equation intersects with the x-axis is the solution.

3. Can I use the quadratic formula to solve for theta in any equation?

No, the quadratic formula can only be used to solve equations in the form of ax^2 + bx + c = 0. In this case, we can convert the given equation to this form by moving all the terms to one side, and then use the quadratic formula to solve for theta.

4. Are there any other methods for solving this equation?

Yes, there are other methods such as using trigonometric identities or factoring to solve for theta in this equation. However, the quadratic formula is the most efficient and straightforward method for solving this specific equation.

5. Can we solve for theta if the equation has a different form?

It depends on the specific form of the equation. If it can be converted to the form ax^2 + bx + c = 0, then we can use the quadratic formula to solve for theta. However, if the equation is in a different form, we may need to use a different method to solve for theta.

Similar threads

Replies
4
Views
504
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
7
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
613
  • Calculus and Beyond Homework Help
Replies
10
Views
2K
  • Precalculus Mathematics Homework Help
Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
13
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
563
  • Calculus and Beyond Homework Help
Replies
1
Views
136
Back
Top