Subjects algebra

Cosine Intersection 7D82Af

Step-by-step solutions with LaTeX - clean, fast, and student-friendly.

Use the AI math solver

1. **State the problem:** Find the x-coordinates where the graphs of \( f(x) = \cos^2(x) + 6\cos(x) \) and \( g(x) = -5 \) intersect for \( 0 \leq x < 2\pi \). 2. **Set the functions equal to find intersection points:** $$ \cos^2(x) + 6\cos(x) = -5 $$ 3. **Rewrite the equation:** $$ \cos^2(x) + 6\cos(x) + 5 = 0 $$ 4. **Use substitution:** Let \( y = \cos(x) \), then the equation becomes: $$ y^2 + 6y + 5 = 0 $$ 5. **Factor the quadratic:** $$ (y + 5)(y + 1) = 0 $$ 6. **Solve for \( y \):** $$ y = -5 \quad \text{or} \quad y = -1 $$ 7. **Check domain of cosine:** Since \( \cos(x) \) ranges from -1 to 1, \( y = -5 \) is invalid. 8. **Solve for \( x \) when \( \cos(x) = -1 \):** On \( [0, 2\pi) \), \( \cos(x) = -1 \) at: $$ x = \pi $$ 9. **Final answer:** The x-coordinate of the intersection point is: $$ \boxed{\pi} $$