TRIGONOMETRIC FUNCTIONS - EXERCISE 2

(a)
Evaluate tex2html_wrap_inline86 (give an exact answer).

(b)
If tex2html_wrap_inline88 and tex2html_wrap_inline90 , find tex2html_wrap_inline92 (give an exact answer).

Solution: (a) Observe that tex2html_wrap_inline94 5 whole revolutions tex2html_wrap_inline96 . Since tex2html_wrap_inline98 has period tex2html_wrap_inline100 , it follows that
tex2html_wrap_inline102 . The angle tex2html_wrap_inline104 lies in the third quadrant and has tex2html_wrap_inline106 as reference angle, therefore tex2html_wrap_inline108 is a point on the angle and on the unit circle, from which we obtain:

displaymath84

(b) Observe that tex2html_wrap_inline110 , from which we obtain that tex2html_wrap_inline112 .

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