Electronic Journal of Differential Equations, Vol. 2005(2005), No. 37, pp. 1-16. Title: Asymptotic shape of solutions to nonlinear eigenvalue problems Author: Tetsutaro Shibata (Hiroshima Univ., Japan) Abstract: We consider the nonlinear eigenvalue problem $$ -u''(t) = f(\lambda, u(t)), \quad u > 0, \quad u(0) = u(1) = 0, $$ where $\lambda > 0$ is a parameter. It is known that under some conditions on $f(\lambda, u)$, the shape of the solutions associated with $\lambda$ is almost `box' when $\lambda \gg 1$. The purpose of this paper is to study precisely the asymptotic shape of the solutions as $\lambda \to \infty$ from a standpoint of $L^1$-framework. To do this, we establish the asymptotic formulas for $L^1$-norm of the solutions as $\lambda \to \infty$. Submitted January 11, 2005. Published March 29, 2005. Math Subject Classifications: 34B15. Key Words: Asymptotic formula; $L^1$-norm; simple pendulum; logistic equation