All you need is the double angle identity:
So we have
Apply the identity again to the squared term:
X is 1 because if you times it by x it equals it number
<span>The best way for Norm to store his money is through C. A money market account paying 3.5% interest, renewable for three-month commitments. Even though a four-year CD offers a higher interest at 4.8%, the fact that there is a substantial penalty for early withdrawal is a negative factor for Norm. His daughter needs the money after 2 years since she is already a junior in high school.</span>
