函数 f(x) = (sinx + cosx)*cosx 的最小正周期为 π.过程写下，谢谢f(x) = (sinx + cosx)*cosx=√2 * ( √2/2 * sinx + √2/2 * cosx ) * cosx=√2 * [ sinx * cos(π/4) + cosx * sin(π/4) ] * cosx=√2 * sin(x + π/4) * cosx=√2/2 * [ sin(2x + π/4) + sin(π/4) ]=√2/2 * [ sin(2x + π/4) + √2/2 ]=√2/2 * sin(2x + π/4) + 1/2其最小正周期为 π。谢了最大值为 (1 + √2)/2