HW
5.3 Back side of notes
1­33 all, in NB, WPF ∀
5.3 NOTES
SOLVING
TRIG EQUATIONS
5.3 SOLVING TRIG EQUATIONS over [0,2 )
NOTE:
To find these answer, you must use the Trig Circle.
These are not inverses, so you do not have to worry
about which quadrant you need to be in.
Important NOTE:
=
=
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5.3 SOLVING TRIG EQUATIONS over [0,2 )
6. cos2x=0
7. cos 2x ­1=0
optional
line
NOTE:
this problem is like
x2 = 0
x x=0
so x = 0
write answers for
each part
underneath before
giving full answer
r #7
o
f
2
ion
opt
therefore,
cos2x=0 means
(cosx)(cosx) = 0
cosx = 0
optional
line
7. cos 2x ­1=0
­sin2x=0
sin2x=0
(sinx)(sinx)=0
sinx=0 sinx=0
9. 4cos2x­2=0
10. 2sinx­√3=0
optional
lines
11. 2cos2x+3cosx­2=0
optional
line
12. sinxtanx=0
tan
tan
13. cotxcos 2x=cotx
1. set equal to zero before trying to solve
2. Ask yourself "What can I take out?"
3. Factor completely
4. Set each piece equal to zero (optional line)
5. Solve for the variables. 6. Write the answers under each part before completing the answer box
HW
5.3 Back side of notes
1­33 all, in NB, WPF ∀