Trig Circular Functions: exact value of sec 7pi/6, etc

[Louise Johnson]

I have three questions I am unsure about. It would be a geat help if someone could let me know if I need to work through them more.

#1 If sinØ<0 and secØ>0, then Ø terminates in quadrant?
answer: quadrant three

#2 The exact value of sec 7pi/6 is ?
Answer - 1/sqrt3

#3 A 2pi cm wire is stretched along a circle of radius 4cm. The degree measure of the central angle subtended by this wire arc is?
Answer 90degrees

Thank you lots and lots!

Louise

 

[pka]

Re: Trig Circular Functions

#1 If sinØ<0 and secØ>0, then Ø terminates in quadrant?answer: quadrant three
No secant is negative in quadrant III.


#2 The exact value of sec 7pi/6 is ?
Answer - 1/sqrt3
No, that does not work.

Try again.

 

[Louise Johnson]

Dear PKA, Thank you for your help
#1 I see where I went wrong.. I read sec to be less than zero. The answer should be quadrant four as sin is neg and sec or cos is pos.

#2 should be one over -sqrt 3/2 because sec is 1 over cos.
The answer is neg 2 over sqrt 3

#3 I hopefully at least got that one correct?

 

[pka]

Very good. Full marks.