4.2 trig functions.notebook -...
TRANSCRIPT
-
4.2 Trig Functions.notebook
1
October 21, 2012
*SohCahToa ppt
Pause & Practice: 4.1 (page 335) #'s (58, 917 odd)
opposite
hypotenuse
adjacent
hypotenuse
opposite
adjacent
2.unknown
We need a way to remember all of these ratios…
Old Hippie
Some
Old
Hippie
Came
A
Hoppin’
Through
Our
Apartment
SOHCAHTOA
Old Hippie
Sin
Opp
Hyp
Cos
Adj
Hyp
Tan
Opp
Adj
q
Sin
Opp
Hyp
=
Cos
Adj
Hyp
=
Tan
Opp
Adj
=
SMART Notebook
-
4.2 Trig Functions.notebook
2
October 21, 2012
Trigonometric Function Value
sin 45°cos 45°tan 45°cosec 45°sec 45°cot 45°
√2 45°
45° 90°
1
1
C
A B
Right triangle of 454590 degrees and unit legs can be used to obtain trigonometric functions at multiples of 45°.1. Draw a line AB of length 5 cm using the Lines tool
with the help of the ruler.2. Take the compass and set its length to 5 cm using the ruler.3. Keep the spike of the compass at A and draw an arc above the line.4. Then keep the spike of the compass at B and draw another arc intersecting the first arc and mark the point of intersection as C.5. Use the ruler and the Lines tool to draw a line from C to A and another from C to B.6. Use the ruler to measure the length of the sides AC and BC to verify that the sides are equal.
454590 Triangle
Hints
Solution
1. Elaborate the point to the students.2. Call a student to obtain the trigonometric functions of sine, cosine, and tangent from the right triangle 454590 given.3. Pull the Hints box, if required, to recall sine, cosine, and tangent ratios of a right triangle.4. Congratulate the student, who completes the task correctly.5. Call another student to obtain the trigonometric functions of cosecant, secant, and cotangent from the right triangle 454590 given.6. Congratulate the student if he or she has completed the task correctly. Pull the Solution box, if required.
Teacher's Notes
Trigonometric Function Value
sin 30°cos 30°tan 30°cosec 30°sec 30°cot 30°
Equilateral triangle can be used to obtain trigonometric functions at multiples of 30°.1. Draw a line AB of length 5 cm using the Lines tool
with the help of the ruler.2. Take the compass and set its length to 5 cm using the ruler.3. Keep the spike of the compass at A and draw an arc above the line.4. Then keep the spike of the compass at B and draw another arc intersecting the first arc and mark the point of intersection as C.5. Use the ruler and the Lines tool to draw a line from C to A and another from C to B.6. Use the ruler to measure the length of the sides AC and BC to verify that the sides are equal.
606060 Triangle
Solution 2
Solution 1
Teacher's Notes 2
5. Congratulate the student, who did the task correctly. Pull the Solution 1 box, if required. 6. Call a student to obtain the trigonometric functions of sine, cosine, and tangent and its coefficients from the right triangle 306090.7. Congratulate the student if he or she has performed the task correctly. Pull the Solution 2 box, if required.
Teacher's Notes 1
1. Elaborate the point to the students.2. Call a student to split the equilateral triangle to 2 congruent triangles and to identify the angles of each vertex for the 2 triangles.3. Congratulate the student, who performs the task correctly.4. Call another student to obtain the length of the side opposite to the angle 60°.
Trigonometric Function Value
sin 60°cos 60°tan 60°cosec 60°sec 60°cot 60°
Using the split triangle of the equilateral triangle obtain trigonometric functions at multiples of 60°.1. Draw a line AB of length 5 cm using the Lines tool
with the help of the ruler.2. Take the compass and set its length to 5 cm using the ruler.3. Keep the spike of the compass at A and draw an arc above the line.4. Then keep the spike of the compass at B and draw another arc intersecting the first arc and mark the point of intersection as C.5. Use the ruler and the Lines tool to draw a line from C to A and another from C to B.6. Use the ruler to measure the length of the sides AC and BC to verify that the sides are equal.
Activity
Solution
Teacher's Notes
1. Elaborate the problem to the students.2. Call a student to obtain the trigonometric functions of sine, cosine, and tangent and its coefficients from the right triangle 306090.3. Congratulate the student if he or she has performed the task correctly. Pull the Solution box, if required.
30°
45°60
°
120°135°150°
210°
225°
240°
300°
315°
330°
sin 60 =
√3/2
cos 60 = 1/2
tan 60= √3
sin 30=
1/2
cos 30 = √3
/2
tan 30 =
1/√3
sin 45 = 1/√2
cos 45 =1/√2
tan 45 =1
Y
X
We can summarize the values of trigonometric functions asUsing the table find value sin, cos, and tan of angles in the diagram. The radius of the circle is 1.
Angle 30° 45° 60° 90°
Sin 1/2 1/√2 √3/2 1
Cos √3/2 1/√2 1/2 0
Cos 1/√3 1 √3 infinity
1. Draw a line AB of length 5 cm using the Lines tool with the help of the ruler.2. Take the compass and set its length to 5 cm using the ruler.3. Keep the spike of the compass at A and draw an arc above the line.4. Then keep the spike of the compass at B and draw another arc intersecting the first arc and mark the point of intersection as C.5. Use the ruler and the Lines tool to draw a line from C to A and another from C to B.6. Use the ruler to measure the length of the sides AC and BC to verify that the sides are equal.
304560 at all Quadrants
Hints
tan (90° – θ) = + cot θ
Solution
Teacher's Notes 2
5. Congratulate the student, who performed the task correctly. 6. Call one student to obtain the trigonometric functions of sine, cosine, and tangent for angles 300, 315, and 330. Pull the Hints box, if required.7. Congratulate the student, who performed the task correctly. Pull the Solution box, if required.
Teacher's Notes 1
1. Explain the table to the students and then the problem to the students.2. Call one student to obtain the trigonometric functions of sine, cosine, and tangent for angles 120, 135, and 150. Pull the Hints box, if required.3. Congratulate the student, who performed the task correctly. 4. Call a student to obtain the trigonometric functions of sine, cosine, and tangent for angles 210, 225, and 240. Pull the Hints box, if required.
-
4.2 Trig Functions.notebook
3
October 21, 2012
THESE ARE SO IMPORTANT!! Try these next practice problems: #'s 1928
Turn to page 332. Go sit with your 12 o'clock appointment and read this page together. Get out your calculators and do some of the mistakes it
describes.
OK, last thing...
-
4.2 Trig Functions.notebook
4
October 21, 2012
Add to your HW #'s 61, 62, 64HW Assignment: 4.2 (pg. 337) #'s 58, 917 odd, 1928, 61, 62, 64
How is this lesson related to the unit circle?
What does this have to do with the paper plate activity?
-
Attachments
SohCahToa.ppt
opposite
hypotenuse
adjacent
hypotenuse
opposite
adjacent
2.unknown
We need a way to remember all of these ratios…
Old Hippie
Some
Old
Hippie
Came
A
Hoppin’
Through
Our
Apartment
SOHCAHTOA
Old Hippie
Sin
Opp
Hyp
Cos
Adj
Hyp
Tan
Opp
Adj
q
Sin
Opp
Hyp
=
Cos
Adj
Hyp
=
Tan
Opp
Adj
=
SMART Notebook
Page 1Page 2Page 3Page 4Attachments Page 1