Posted by **John** on Thursday, March 5, 2009 at 8:09pm.

if sin s = -5 /13

and sin t -3/5

s is in QIII

t is in QIV

find tan (s-t)

i got that tan (s-t)= 56/53

is that right? can someone check my work?

- TRIG -
**drwls**, Thursday, March 5, 2009 at 11:58pm
If sin s = -5/13, and it is in the third quadrant, cos s = -12/13

s = 202.620 degrees

If sin t is -3/5, and t is in the fourth quadrant, cos t = 4/5.

t = 323.130 degrees

tan (s-t) = sin (s-t)/cos(s-t)

= [sin s cos t - sin t cos s]/

[cos s cos t + sin s sin t]

Crunch the numbers. You should get a rational fraction, but your 53 in the denominator looks fishy.

You answer should be 56/33.

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