B. 5.5×(7.5×6.4) =(5.5×7.5)×6.4
Let's do the trig part first, then the calculus. First we simplify the integrand.

The triple angle formula is:

or

Now we can integrate:



Because, when you divide you can use place value to break the equation up and make it easy. Example: 142/2. 140/2=70 and 2/2=1 add 70 +1=71. So 142/2=71