In a precision engineering simulation, the vertical displacement hhh of a micro-lever is modeled by the equation h=15cos(4θ)−6h = 15\cos(4\theta) - 6h=15cos(4θ)−6, where θ\thetaθ is a small angle measured in radians. Using small angle approximations, find a simplified expression for hhh in terms of θ\thetaθ.