sinx+cosx
=√2sin(x+π/4)
(1)当x∈[0,π]
x+π/4∈[π/4,5π/4]
√2sin(x+π/4)∈[-1,√2]
有且只有一个解
从图像得
2m∈[-1,1)
m∈[-1/2,1/2)
(2)当x∈R
√2sin(x+π/4)∈[-√2,√2]
2m∈[-√2,√2]
m∈[-√2/2,√2/2]
(3)x∈[0,2π]
x+π/4∈[π/4,9π/4]
√2sin(x+π/4)∈[-√2,√2]
有两解α,β
1
sinx+cosx
=√2sin(x+π/4)
(1)当x∈[0,π]
x+π/4∈[π/4,5π/4]
√2sin(x+π/4)∈[-1,√2]
有且只有一个解
从图像得
2m∈[-1,1)
m∈[-1/2,1/2)
(2)当x∈R
√2sin(x+π/4)∈[-√2,√2]
2m∈[-√2,√2]
m∈[-√2/2,√2/2]
(3)x∈[0,2π]
x+π/4∈[π/4,9π/4]
√2sin(x+π/4)∈[-√2,√2]
有两解α,β
1