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7.2 V
Iden
Trig
Suggestions for Verifying Trig Identities:
• Transform the more complicated side of the
equation into the simpler side.
• Substitute one or more basic trig identities (from
section 7.1) to simplify expressions.
• Factor or multiply to simplify expressions.
• Multiply expressions by an expression equal to 1.
• Express all trig functions in terms of sine and
cosine.
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Examples: Verify that each equation is an identity.
1.) tanA = secA
cscA
2.) secx - tanx = 1 - sinx
cosx
3.) secxcscx = tanx + cotx
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4.) cosy = 1 + siny
1 - siny cosy
5.) sinx + cosx = cosx +
1 - tanx
sinx
1 - cotx
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Examples: Find a numerical value of one trig function of x.
1.) cscx = √2
cotx
2.) 1 + cosx +
sinx = 4
sinx
1 + cosx
7.2 Homework: pages 434-435: 14-34 even
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