He subtracted the 29fron the 30
Page 1 is B, page 2 is B, page 3 D, page 4 D ( prity sure not 100%), page 5 you posted it twice
The two integers that sum is 101 is 20.2 and 1
Sin 3pi/4 is angle 135 degrees or 45 degrees below 180 degrees. Hence it's opposite side is 1 and adjacent is 1, implying the hypothenus is sqrt(2). Hence
Sin 3pi/4 = 1/sqrt(2). Now multiply by sqrt(2)/sqrt(2) to get:
[1/sqrt(2).] * [sqrt(2)/sqrt(2)] = sqrt2)/2
