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(1)√(sin^2(500°)+sin^2(770°)-cos^2(1620°-x),x∈(180°,270°)(2)sin(x-5π)/cos(3π-x)*cos(8π-x)/sin(x-3π)*cos(8π-x)/sin(-x-4π)-sinx(3)√1+2sin290°cos430°/sin250°+cos790°(4)cos[(3k

题目详情
(1)√(sin^2 (500°)+sin^2( 770°)-cos^2(1620°-x),x∈(180°,270°)
(2)sin(x-5π)/cos(3π-x)*cos(8π-x)/sin(x-3π)*cos(8π-x)/sin(-x-4π)-sinx
(3)√1+2sin290°cos430°/sin250°+cos790°
(4)cos[(3kπ+π/3)+x]+cos[(3kπ-π/3)-x](k属于Z)
▼优质解答
答案和解析
(1)√(sin^2 (500°)+sin^2( 770°)-cos^2(1620°-x),x∈(180°,270°)=√(sin^2 (140°)+sin^2( 50°)-cos^2(180°-x),=√(sin^2 (40°)+sin^2( 50°)-cos^2(180°-x),=√(cos^2 (50°)+sin^2( ...