求值[tan(-330)cos(-570)cos150sin(-420)]/[cos(-420)sin(-690)]
问题描述:
求值[tan(-330)cos(-570)cos150sin(-420)]/[cos(-420)sin(-690)]
答
[tan(-330)cos(-570)cos150sin(-420)]/[cos(-420)sin(-690)]=[tan(-360+30)cos(-720+150)cos150sin)]/[cos(-360-60)sin(-720+30)](360度整倍数直接拿出)=[tan(30)cos(150)cos150sin(-60)]/[cos(-60)sin(30)]= -[tan...