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√2sin(x/2+π/4)cos(x/2)=√2/2sin(x+π/4)+1/2怎么得到的
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√2sin(x/2+π/4)cos(x/2)=√2/2sin(x+π/4)+ 1/2 怎么得到的
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答案和解析
√2sin(x/2+π/4)cos(x/2)
=√2(sin(x/2)cosπ/4+sinπ/4cos(x/2))cos(x/2)
=√2(√2/2sin(x/2)+√2/2cos(x/2))cos(x/2)
=sin(x/2)cos(x/2)+cos²(x/2)
=sin2x/2+(1+cos2x)/2
=sin2x/2+cos2x/2+1/2
=(√2/2)[sin2x(√2/2)+cos2x(√2/2)]+1/2
=(√2/2)[sin2xcosπ/4+cos2xsinπ/4]+1/2
=√2/2sin(x+π/4)+ 1/2
很高兴为您解答,skyhunter002为您答疑解惑
如果本题有什么不明白可以追问,
=√2(sin(x/2)cosπ/4+sinπ/4cos(x/2))cos(x/2)
=√2(√2/2sin(x/2)+√2/2cos(x/2))cos(x/2)
=sin(x/2)cos(x/2)+cos²(x/2)
=sin2x/2+(1+cos2x)/2
=sin2x/2+cos2x/2+1/2
=(√2/2)[sin2x(√2/2)+cos2x(√2/2)]+1/2
=(√2/2)[sin2xcosπ/4+cos2xsinπ/4]+1/2
=√2/2sin(x+π/4)+ 1/2
很高兴为您解答,skyhunter002为您答疑解惑
如果本题有什么不明白可以追问,
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