高一数学填空题,急,各位大神
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高一数学填空题,急,各位大神
![高一数学填空题,急,各位大神](/uploads/image/z/4163764-4-4.jpg?t=%E9%AB%98%E4%B8%80%E6%95%B0%E5%AD%A6%E5%A1%AB%E7%A9%BA%E9%A2%98%2C%E6%80%A5%2C%E5%90%84%E4%BD%8D%E5%A4%A7%E7%A5%9E)
12、f(-x)=(-x)^3+sin(-x)+1=-f(x)+2,所以f(-a)=f(a)+2=5
13、sin50°(1+√3tan10°)=sin50°[(cos10°+√3sin10°)/cos10°]=2sin50°(1/2cos10°+√3sin10°)/cos10° =2sin50°cos50°/cos10° =sin100°/cos10° =sin80/cos10° =1
14、设2^x=t,则t≥1,f(x)=t²-at(t≥1),对称轴为t=a/2,若a/2≤1,即a≤2,则有1-a=-4,得a=5,不符合题意.若a/2>1,即a>2,有a²/4-a²/2=-4,得a=-4(舍去)或a=4,综上,a=4
15、①②
再问:![](http://img.wesiedu.com/upload/4/4f/44f81a4aeedb70aec977ab419c309387.jpg)
再答: 1、f(x)=-√2(√2/2sin2x+√2/2cos2x)+3sin2x-2X(cos2x+1)/2=-sin2x-cos2x+3sin2x-cos2x-1=2sin2x-2cos2x-1=2√2sin(2x-π/4)-1,最小正周期为π 2、x∈[0,π/2],2x-π/4∈[-π/4,3π/4],sin(2x-π/4)∈[-√2/2,1],所以最大值为2√2-1,最小值为-3
13、sin50°(1+√3tan10°)=sin50°[(cos10°+√3sin10°)/cos10°]=2sin50°(1/2cos10°+√3sin10°)/cos10° =2sin50°cos50°/cos10° =sin100°/cos10° =sin80/cos10° =1
14、设2^x=t,则t≥1,f(x)=t²-at(t≥1),对称轴为t=a/2,若a/2≤1,即a≤2,则有1-a=-4,得a=5,不符合题意.若a/2>1,即a>2,有a²/4-a²/2=-4,得a=-4(舍去)或a=4,综上,a=4
15、①②
再问:
![](http://img.wesiedu.com/upload/4/4f/44f81a4aeedb70aec977ab419c309387.jpg)
再答: 1、f(x)=-√2(√2/2sin2x+√2/2cos2x)+3sin2x-2X(cos2x+1)/2=-sin2x-cos2x+3sin2x-cos2x-1=2sin2x-2cos2x-1=2√2sin(2x-π/4)-1,最小正周期为π 2、x∈[0,π/2],2x-π/4∈[-π/4,3π/4],sin(2x-π/4)∈[-√2/2,1],所以最大值为2√2-1,最小值为-3