Trigonometry Day 2
June 03, 2011
HW: Trigonometry Packet Section 10-3 #5, 6, 9, 11 - 13, 15, 16
DO NOW:
Questions from HW that was due Wednesday?
(From textbook, page 344 #15)
A football kicker tries to make a field goal with the ball on the 25
yard line (105 feet from the goal posts). If you imagine a
coordinate system with the ball being kicked at x=0 and the goal
post at x=105, then the equation of the ball's path is
where y is the ball's height in feet.
a) What is the maximum height of the ball?
b) Will the ball clear the goal post crossbar that is 10 ft above the
ground?
As a way to make sure that students are clear on what they need
to know about quadratics for the final exam, I am assigning a
short graded assignment that is due next Tuesday at the
beginning of class. I will give you some time to look at this
assignment and work on it now and ask questions.
After lunch, we will go back to working on Trigonometry.
1
Trigonometry Day 2
June 03, 2011
How do we use trigonometry to solve problems?
1) If we are given one acute angle, and one leg of a
triangle, we can use the TANGENT ratio to find the other
leg of the triangle. If we wanted to know the hypotenuse,
we could then use the Pythagorean Theorem.
2) If we are given both legs of a right triangle, we can use
the INVERSE TANGENT to find the measure of an acute
angle. Again, we could use Pythagorean Theorem to find
the hypotenuse.
Examples:
1) We know that Tan 39°=x/23
so x=23 Tan 39°=
39°
x
23
Try problems #2-4 from Section 10-3
2) We know that TAN A=42/35
-1
so, A = TAN (42/35)
42
A
35
Try problems #7-8 from Section 10-3
2
Trigonometry Day 2
June 03, 2011
Two new terms you need to learn:
Look on the front page of the packet
ANGLE OF ELEVATION: If you are
standing at the bottom, looking up,
the angle you raise your sight from
the horizontal
ANGLE OF DEPRESSION: If you are
standing at the top, looking down, the
angle you lower your sight from the
horizontal
Angle of Elevation
Angle of Depression
Let's do problems 10 and 14 together.
10)
14)
3