求计算题:cos315°+sin(-30°)+sin135°+cos480°

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求计算题:cos315°+sin(-30°)+sin135°+cos480°
求计算题:cos315°+sin(-30°)+sin135°+cos480°

求计算题:cos315°+sin(-30°)+sin135°+cos480°
=cos(360°-45°)+sin(-30°)+sin(180°-45°)+cos(360°+120°)
=cos(-45°)+sin(-30°)-sin(-45°)+cos120°
=cos45°-sin30°+sin45°+cos(180°-60°)
=cos45°-sin30°+sin45°-cos60°
结果是根号2减1

0.4142

=cos(-45)-sin30+cos45+cos120
=cos45-sin30+cos45-sin30
=根号2减1

=根号2减1

根号2减1

=cos(360°-45°)+sin(-30°)+sin(180°-45°)+cos(360°+120°)
=cos(-45°)+sin(-30°)-sin(-45°)+cos120°
=cos45°-sin30°+sin45°+cos(180°-60°)
=cos45°-sin30°+sin45°-cos60°
根号2减1