academy algebra ii pre-calculus (5.1, 5.2) 14.3: trigonometric identities hw: today: none, hw...
TRANSCRIPT
Academy Algebra IIPre-Calculus (5.1, 5.2)
14.3: Trigonometric IdentitiesHW: today: none,
HW tomorrow: p.928 (16-34 even)
Trig Identities• Reciprocal Identities
• Quotient Identities
uu
uu
uu
uu
uu
uu
tan
1cot
cos
1sec
sin
1csc
cot
1tan
sec
1cos
csc
1sin
u
uu
u
uu
sin
coscot
cos
sintan
Trig Identities• Pythagorean Identities
• Even/Odd Identities
uu
uu
uu
22
22
22
csccot1
sectan1
1cossin
uuuu
uuuu
uuuu
cot)cot( tan)tan(
sec)sec( cos)cos(
csc)csc( sin)sin(
Trig Identities• Cofunction Identities
uuuu
uuuu
uuuu
sec2
csc csc2
sec
tan2
cot cot2
tan
sin2
cos cos2
sin
Simplify the Trig Expressionxxx sincossin 2
Simplify the Trig Expression))(secsin1( 2 xx Check using your calculator:
Y1= Question
Y2= Answer
Check: graphs/tables are the same
Verify.
xxx
xtansin
cos2
cos2
Verify the Identity Algebraically. 22 sincosseccos
Verify the Identity Algebraically.
seccoscot
csc1
Factor the expression and simplify.xxx 222 sectansec
5.2: Verifying Trig Identities1.) Work with one side of the equation.2.) Algebra: Look for opportunities to factor an expression, add fractions, square a binomial, or create a monomial denominator.3.) Trig: Look for opportunities to use the fundamental identities.4.) If the preceding guidelines do not help, try converting to all sines and cosines.5.) Try something! Even making an attempt that leads to a dead end gives insight.
Verify.1csc
1csc
1csc2
xx
x
Multiply and simplify. xxxx csccotcsccot
Verify.x
xx2cot2
1sec
1
1sec
1
Verify the Identity.
22
2
sinsec
1sec
Verify the Identity.
2sec2
sin1
1
sin1
1
Verify the Identity. xxx 222 tan1cos1tan
Verify the Identity.xxxx cscseccottan
Verify the Identity.
x
xxx
sin1
costansec
Verify the Identity.
sin
sin1
csc1
cot 2