TRIGONOMETRY

[Guest]

@ = THETA

describe an interval between 0 and 2pi in which @ satisfies the given requirements

Can someone tell me if my answers are correct?


1. sin @ > 0 and then tan @ < 0

MY ANSWER: 90 < @ < 180


2. cos @ = 0 and sin @ > 0

MY ANSWER: 90< @ < 360


3. tan @>0 and cos @< 0

MY ANSWER: 180<@<270

 

[Guest]

answers fro 1 & 3 look correct,
however for #2......

cos@ = 0 at 90 or 270 degrees and sin @ >0 implies a positive result which can only occur at 90 degrees.

So the answer for this one is 90 degrees

 

[arthur ohlsten]

1 sin is positive 0<@<pi
tan is positive 0<@pi/2 and pi<@<3pi/2

answer 0<@pi/2

2 cos @=0 at pi/2 and 3pi/2
sin positive 0<@pi

answer @=pi/2

3 tan@>0 0<@<pi/2 and pi<@<3pi/2
cos@<0 pi/2<@3pi/2

answer poi<@<3pi/2
Arthur