Section 9­3 Trig B.notebook
February 02, 2017
Finishing up Section 9.2
Solve the system of equations for 0 < θ < 2π :
r = 3 ­ 3sinθ
r = 4 ­ sinθ
9.3 Polar & Rectangular Coordinates
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I can convert between polar and rectangular coordinates and equations.
To convert polar coordinates (r, θ) to rectangular coordinates (x, y):
x = r cos θ
y = r sin θ
Dec 1­8:34 AM
Convert (3, 270o) to rectangular coordinates.
Feb 27­4:16 PM
To convert rectangular coordinates to polar coordinates you can use the Pythagorean Th. and Arctan function. You must take note of the quadrant the point lies in to find the value of θ.
Jan 8­9:12 AM
Convert (­2, ­5π/6) to rectangular coordinates.
Feb 27­4:17 PM
Convert (3, ­4) to polar coordinates.
Convert (3, 4) to polar coordinates.
Convert (­3, 4) to polar coordinates.
Jan 8­9:15 AM
Feb 27­4:20 PM
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Section 9­3 Trig B.notebook
Sec. 9.2 p. 565
#24, 26, 39
Finish Worksheet
February 02, 2017
Helpful formulas:
r2 = x2 + y2
r = √ x2 + y2
x = r cos θ
Sec. 9.3 p. 572 #15 ­ 25 odd, 40, 49
Feb 1­7:33 AM
y = r sin θ
Jan 8­9:18 AM
Writing polar equations in rectangular form:
Writing a rectangular equation in polar form:
Example: r = 6 cosθ
Example: (x ­ 3)2 + y2 = 9
Ex: r = ­3
Try this: x2 + (y ­ 1)2 = 1
2
Ex: r + 4rcosθ = 0
Jan 8­9:23 AM
What is y = x in polar form? (use Mental Math)
Jan 8­9:25 AM
Assignment: Sec. 9.3 p. 572 #15 ­ 39 (odds, skip #33), 40, 49
WRITE DOWN THE PROBLEM & SHOW YOUR WORK!
What is x = ­7 in polar form?
Jan 8­9:31 AM
Dec 2­10:38 AM
2