求函数y=2cos(2x+π/3),x属于[-π/6,π/6]的最大值和最小值

Question

求函数y=2cos(2x+π/3),x属于[-π/6,π/6]的最大值和最小值

Answer 1

x∈[-π/6,π/6]
2x∈[-π/3,π/3]
2x+π/3∈[0,2π/3]
所以当2x+π/3=0时,有最大值y=2
当2x+π/3=2π/3时,有最小值y=-1