Math 120:
Pre-calculus 2
Instructor: Mike Panitz
(mpanitz@cascadia.ctc.edu)
Today
• Sum & Difference Formulas
– Section (7.4 / 4e (9.4 / 3e))
• Double & Half-Angle Formulas:
– Section (7.5 / 4e (9.5 / 3e))
• Exam #1 Review
Math 120: Pre-Calculus 2!
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Next Lecture
• Sum-to-Product/Product-To-Sum Formulas
– Section (7.6 / 4e (9.6 / 3e))
• Trig Equations:
– Section (7.7-7.8 / 4e (9.7-9.8 / 3e))
Math 120: Pre-Calculus 2!
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Homework
• All homeworks will be collected on the day
of the next exam (Feb 22nd)
– Collected at the beginning of class
– Hand them in before you start the exam
Math 120: Pre-Calculus 2!
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End of lecture slides
Math 120: Pre-Calculus 2!
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Exam #1
• Good, overall
• You now own it
– Save it to study for exam #2, final from
• We’ll go over things I think people had
trouble with
– These are likely to show up on exam #2, final
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• Finding trig functions by identity
– Do not draw a triangle – do this all
algebraically
– See Exam Prep #1 for an example solution
– Make sure you know this, for Exam #2, final!
 
 
 



tan
35

sec
55

sin
55
•
– Complementary angles!
• Establishing an identity
– NOT AN EQUATION!!
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• Amplitude/Period/Phase Shift
– Phase shift is the amount the equation is shifted
RIGHTWARDS by
– Therefore, you’ll SUBTRACT that amount, in
the equation
• Proving that Sin(45 or 30) is X:
– Start with definition of sin, and that angle
– Show how to get the appropriate special
triangle
– Then use the definition to get X
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Question Redo
• Next Tuesday (Feb 14th)
• I’ll pick one or two questions from the
exam
– I’ll create a ‘quiz’ based on those questions
– Not those questions exactly, but the questions
will be similar (i.e., different numbers, different
expression, etc)
• The quiz will count as “extra credit” points,
to be added to your Exam #1 grade.
Math 120: Pre-Calculus 2!
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