问题 填空题

sin80°cos35°-sin10°cos55°=______.

答案

sin80°cos35°-sin10°cos55°

=sin(90°-10°)cos35°-sin10°cos(90°-35°)

=cos10°cos35°-sin10°sin35°

=cos(10°+35°)

=cos45°

=

2
2

故答案为:

2
2

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