Ma'am I'm sorry i couldn't attend this class (april 21st trigonometric functions) as i was out of station.So i watched the recorded video of the class and i did no understand the eg of sec(570) which you did freehand.I haven't understood how it can be written as (5*90+30) .Also since it falls in the 2nd quadrant and since sec is changed to cosec, shouldn't the answer be cosec(30) instead of being -cosec(30)?