Question

6cos(20πt-π)+6√3cos(20πt-π\2)

Answer 1

Answer is -6t

Explanation:

`{ \tt{ = (6 \cos(20\pi t) \cos(\pi) + 6\sin(20\pi t) \sin(\pi) ) + 6 √(3) ( \cos(20\pi t) \cos( (\pi)/(2) ) + \sin(20\pi t) \sin( (\pi)/(2) )) }} \\ = { \tt{ (- 6t + 0) + (0 + 0)}} \\ = { \tt{ - 6t}}`

Note that π is 180°