Helpppl please answer these two questions

What is the number 321,000,000 in scientific notation? also what is the number? ?

Axel follows these steps to divide 40 by 9: start with 40. 1. divide by 9 and write down the remainder. 2. write a zero after the remainder. 3. repeat steps 1 and 2 until you have a remainder of zero. examine his work, and then complete the statements below.

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.