Question

数学题目急!高分!觉得表达不清的可以将过程照下来发彩信到1340228150,有分加!觉得图看不清楚的话发个短信来,我可

Answer 1

f(x)=2cosx(sinx-cosx)+1

=2sinxcosx-2(cosx)^2+1

=sin2x-cos2x-1+1

=√2(√2/2*sin2x-√2/2*cos2x)

=√2(sin2xcosπ/4-cos2xsinπ/4)

=√2sin(2x-π/4)

∵x∈[π/8,3π/4],得 0