Posted by What?! on Monday, June 30, 2008 at 8:39pm.
Two math students erect a sun shade on the beach. The shade is 1.5 m tall, 2 m wide, and makes an angle of 60° with the ground. What is the area of shade that the students have to sit in at 12 noon (that is, what is the projection of the shade onto the ground)? (Assume the sun’s rays are shining directly down)
I did this: a b cos60/^2 and then multiplied the whole thing by 2 (because it is b) I wound up with an answer of 0.75. Is this correct?

Calculus  bobpursley, Monday, June 30, 2008 at 9:07pm
I don't understand your logic. The projection of the area on the ground is ab*cos60, which is not .75m^2

Calculus  Derek, Monday, June 30, 2008 at 9:15pm
My logic was this, as stated from a text book, which also showed your way: the projection of vector a onto b is found by (magnitude a)(magnitude b)(vector b) all over (magnitude b)2

Calculus  bobpursley, Tuesday, July 1, 2008 at 9:34am
This is not a projection of a vector, it is a projection of area.