题目内容
求值:［2sin50°+sin10°(1+
tan10°)］·
.
解:原式=(2sin50°+sin10°)·sin80°
=(2sin50°+2sin10°
)·
cos10°
=2
［sin50°cos10°+sin10°·cos(60°-10°)］
=2
sin(50°+10°)=2
×
=
.
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tan10°)］·.题目内容
求值:［2sin50°+sin10°(1+tan10°)］·.
解:原式=(2sin50°+sin10°)·sin80°
=(2sin50°+2sin10°)·cos10°
=2［sin50°cos10°+sin10°·cos(60°-10°)］
=2sin(50°+10°)=2×=.
-θ）+tan(
+θ)+
tan(
+θ)·tan(
-θ);
tan10°)］·
.
tan10°)］·
．