14. Important Idea
When you
cannot get
exact values
for solutions,
you must use
the inverse trig
functions on
your calculator.
1
sin x−
1
cos x−
1
tan x−
•
•
•
15. Try This
Solve for the principal
value in degrees:
8cos 5 0θ − =
51.318x = °
28. Important Idea
2 2
sin cos 1x x+ =
2 2
sin 1 cosx x= −
2 2
cos 1 sinx x= −
Trigonometric Identities:
2 2
tan 1 secx x+ =
2 2
1 cot cscx x+ =
See
section 6.5
of your text
for
additional
trig
30. Try This
Solve for principal values
in radians:
2
sec 2tan 3x x− =
x=1.220 and x= -.632
31. Important Idea
When solving trig identities,
try one or more of the
following:
•Factor if possible
•Use quadratic formula if you
can’t factor
•Use identities to write the
equation in terms of only one
trig function.