Use the Addition Formula for Cosine to prove the Double-Angle Formula for Cosine. cos(2x) = cos2(x) − sin2(x) Rewrite 2x as x + x, and use the Addition Formula for Cosine to simplify. cos(2x) = cos(x + x) = cos(x) cos(x)

Answer with Step-by-step explanation:

We are given that

LHS

To prove that

We know that

Using the formula

By using

LHS=RHS

Hence, proved.

total amount of money that he should pay if he has not used his duty free exemption is $98

step-by-step explanation:

given a united states citizen returning to the states declares the following items at the customs office: 3 shirts at $8.50 each 2 dresses at $27.50 each 1 pair of gold cuff links at $17.50 per pair. we have to find how much he pay

cost of 3 shirts if one cost at $8.50 is

cost of 2 dresses if one cost at $27.50 is  

cost of 1 pair of gold cuff at $17.50

so, total amount of money that he should pay if he has not used his duty free exemption is   $25.5+$55+$17.50=$98