radians v. degrees
is it on the unit circle?
is it the same?
find the other angle
solving problems
100
change 110 degrees to radians
11pi/18
100
is (1,0) on the unit circle?
yes, 1^2 + 0^2 = 1
100
does cos 25 = cos 155?
NO!
100
what is the other angle on a unit circle that has the same cosine as 45 degrees?
315 (cosine reflects across the x axis)
100
6sinx+5=9
x=41.8
200
change 2pi/3 to degrees
120 degrees
200
is (2, 0) on the unit circle?
no, 2^2 + 0^2 does not equal 1
200
is sin 9pi/4 equal to sin pi/4?
YES! (change radians to degrees first)
200
what is the other angle on the unit circle that has the same sine as 180 degees?
0 degrees. sine reflects across the y axis.
200
sin squared of 35 degrees + cos squared of 35 degrees = ?
1. sin squared + cos squared always equals 1 no matter the angle.
300
change 90 degrees to radians
pi/2
300
is (1/2, sq rt 2) on the unit circle?
no .5^2 + 1.4142 ^2 does not equal 1
300
does cos 55 = cos 35?
NO!
300
what angle between 0 and 360 is in the same location as 525 degrees?
165 degrees
300
if sine of an angle is .78, what is the cosine of that same angle?
.6266 because.... sin x = .78, so inverse sin .78=51.2. so the degree is 51.2. then cos 51.2 =.6266
400
change 4pi/3 to degrees
120 degrees
400
is (-3/5, -4/5) on the unit circle?
yes, -.6^2 + -.8^2 =1
400
does sine squared + cosine squared = 0?
NO!, it equals 1
400
what other angle on the unit circle has the same location as -25 degrees?
335 degrees
400
if sin > 0 and cos < 0 , which quadrant would you be in?
quadrant II because (cos, sin) so (-, +)
500
change 270 degrees to radians
3pi/2
500
is (4/5, 1/5) on the unit circle?
no, .8^2 + .2^ 2 does not equal 1
500
does sin 50= cos (90-50)?
YES! sine of an angle= cosine of 90 MINUS that angle!
500
what other angle has the same cosine as 100 degrees?
260. cosine reflects across the x axis.
500
daily double if cos x=3/4 what is sin x?
.6643 inverse cosine of 3/4 =41.4. sin 41.4=.6613
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