00:01
Okay, we want to simplify the inverse sine of cosine theta, where theta is between 0 and pi over 2.
00:11
Okay, so i'll draw a right triangle with angle theta.
00:19
And let me just label the sides a, b, and my hypotenuse c.
00:25
Okay, so then i see that cosine of theta is equal to the adjacent side, which is a, over the hypotenuse, which is c.
00:38
So then we plug this into the expression and we get inverse sine of a over c.
00:48
So now let's consider this angle here.
00:52
Okay, we know that the total angle in a triangle is pi.
00:57
Okay, so if we subtract these two angles from pi, we will get the value of this angle.
01:04
So pi minus the right angle, which is pi over 2, minus theta, is equal to this angle...