Question

# Error Analysis A student solved the equation 2cos θ = √2 for 0 ≤ θ < 2π and got θ = (π/4). What was her error?

Analyzing functions
Error Analysis A student solved the equation $$2\cos\theta=\sqrt{2}\ for\ 0\leq\theta<2\pi$$ and got $$\theta=(\pi/4)$$. What was her error?
$$\cos\theta=(\frac{\sqrt2}{2})\to\theta=\pi/4\ and\ \theta=\frac{7\pi}{4}$$