- Problem Statement
- Proof of the inequality ##cosx \ge (1-x^2/2##

- Relevant Equations
- ##1\ge cosx \ge 0##

How can the inequality ##cosx \ge(1-x^2/2)## be proved? Would you please explain how to prove this inequality?

This is the only equation that I could think of. ##1\ge cosx \ge 0## but I cannot use it here.

Source: Thomas's Calculus, this is from an integration question there.

Thank you.

This is the only equation that I could think of. ##1\ge cosx \ge 0## but I cannot use it here.

Source: Thomas's Calculus, this is from an integration question there.

Thank you.