奇函數(shù)。奇函數(shù)的乘法函數(shù)是奇函數(shù)。另外，偶函數(shù)乘偶函數(shù)是偶函數(shù)，奇函數(shù)乘奇函數(shù)是偶函數(shù)。函數(shù)的奇偶性是指關(guān)于原點(diǎn)對稱點(diǎn)的函數(shù)值相等，這是函數(shù)的基本性質(zhì)，即它們的像具有一元函數(shù)的某種對稱性。奇函數(shù)乘數(shù)函數(shù)是奇函數(shù)，奇函數(shù)加減奇函數(shù)是奇函數(shù)，偶函數(shù)加減偶函數(shù)是偶函數(shù)，奇函數(shù)乘以奇函數(shù)是偶函數(shù)，偶函數(shù)乘數(shù)函數(shù)是偶函數(shù)。判斷函數(shù)的奇偶性，首先要看定義域。如果定義域關(guān)于原點(diǎn)對稱，我們就討論奇偶性，否則直接判斷奇偶函數(shù)。