初一数学同步答案3.5×1又1/4+125%+1又1/2÷4/5

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初一数学同步答案3.5×1又1/4+125%+1又1/2÷4/5初一数学同步答案3.5×1又1/4+125%+1又1/2÷4/5初一数学同步答案3.5×1又1/4+125%+1又1/2÷4/53.5×

初一数学同步答案3.5×1又1/4+125%+1又1/2÷4/5
初一数学同步答案3.5×1又1/4+125%+1又1/2÷4/5

初一数学同步答案3.5×1又1/4+125%+1又1/2÷4/5
3.5×1又1/4+125%+1又1/2÷4/5
=3.5×1.25+1.25+1.5×1.25
=(3.5+1+1.5)×1.25
=6×1.25
=7.5

f(x)=sin2x+(1-2sin²x)-1
=sin2x+cos2x-1
=√2(√2/2*sin2x+√2/2cos2x)-1
=√2(sin2xcosπ/4+cos2xsinπ/4)-1
=√2sin(2x+π/4)-1
T=2π/2=π
-1<=sin(2x+π/4)<=1
所以sin(2x+π/4)=1时最大
所以2x+π/4=2kπ+π/2
x=kπ+π/8
所以x∈{x|x=kπ+π/8},f(x)最大值=√2-1