赞 huisaisi 春芽
共回答了19个问题采纳率：94.7% 举报
2(√2)
原式={2sin50°+cos10°+√3sin10°}/cos5°
={2sin50°+2[1/2cos10°+√3/2sin10°]}/cos5°
={2sin50°+2[sin30°cos10°+cos30°sin10°}/cos5°
={2sin50°+2sin(30°+10°)}/cos5°
=2{sin50°+sin40°}/cos5°
=2√2{√2/2sin50°+√2/2cos50°}/cos5°
=2√2{cos45°sin50°+sin45°cos50°}/cos5°
=2√2{sin(45°+50°)}/cos5°
=2√2sin95°/cos5°
=2√2cos5°/cos5°
=2√2
原式={2sin50°+cos10°+√3sin10°}/cos5°
={2sin50°+2[1/2cos10°+√3/2sin10°]}/cos5°
={2sin50°+2[sin30°cos10°+cos30°sin10°}/cos5°
={2sin50°+2sin(30°+10°)}/cos5°
=2{sin50°+sin40°}/cos5°
=2√2{√2/2sin50°+√2/2cos50°}/cos5°
=2√2{cos45°sin50°+sin45°cos50°}/cos5°
=2√2{sin(45°+50°)}/cos5°
=2√2sin95°/cos5°
=2√2cos5°/cos5°
=2√2
1年前
1
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