Use your graphing calculator to graph
y = cos^−1(x)in degree mode. Use the graph with the appropriate command to evaluate each expression.
(a)cos^−1(√2/2)
= ___________˚
(b)cos^−1(-1/2)
= _____________°
(c)arccos (√3/2)
= _____________˚
What is arccos?
How do I solve these using the graph? I put it in my calculator but the graph did not show up :/
2 answers
Learn how to use your calculator.
arccos is the inverse cosine.
If x = cos(y) then y = arccos(x)
Mosey on over to
http://rechneronline.de/function-graphs/
and enter arccos(x) for the function. Then set the x and y ranges from -1 to 1 and draw the graph. You can then get a feel for the y values needed. They will be in radians, however. If you want to read them off in degrees, enter
arccos(x) * 180/pi
and set the y range from 0 to 180
As a check, remember that
cos pi/4 = √2/2
cos 2pi/3 = -1/2
cos pi/6 = √3/2
If x = cos(y) then y = arccos(x)
Mosey on over to
http://rechneronline.de/function-graphs/
and enter arccos(x) for the function. Then set the x and y ranges from -1 to 1 and draw the graph. You can then get a feel for the y values needed. They will be in radians, however. If you want to read them off in degrees, enter
arccos(x) * 180/pi
and set the y range from 0 to 180
As a check, remember that
cos pi/4 = √2/2
cos 2pi/3 = -1/2
cos pi/6 = √3/2
4 answers