Here's another way to do this
tan 12t / sin4t =
(sin12t/cos12t) / sin4t = (divide numerator and denominator by t)
(sin12t/t) /[(sin4t/t)(cos12t)] = (multiply the numerator by 12/12 and the denominator by 4/4)
(12sin12t/12t) / [ (4sin4t/4t)(cos12t)]
Now
lim t → 0 (12sin12t/12t) = 12 and
lim t → 0 (4sin4t/4t) = 4 and
lim t → 0 (cos12t) = 1 so
12/(4 * 1 ) = 12/4 = 3
limt→0tan12tsin4t=limt→0sin12tcos12tsin4t=limt→0sin4tcos8t+cos4tsin8tcos12tsin4t=limt→0sin4tcos8t+cos4t∗2sin4tcos4tcos12tsin4t=limt→0cos8t+cos4t∗2cos4tcos12t=cos0+cos0∗2cos0cos0=1+1∗2∗11=3
.Here's another way to do this
tan 12t / sin4t =
(sin12t/cos12t) / sin4t = (divide numerator and denominator by t)
(sin12t/t) /[(sin4t/t)(cos12t)] = (multiply the numerator by 12/12 and the denominator by 4/4)
(12sin12t/12t) / [ (4sin4t/4t)(cos12t)]
Now
lim t → 0 (12sin12t/12t) = 12 and
lim t → 0 (4sin4t/4t) = 4 and
lim t → 0 (cos12t) = 1 so
12/(4 * 1 ) = 12/4 = 3