PROVE THAT:

cos 20° - sin 20° = \sqrt{2}sin25°

See below.

Step-by-step explanation:

First, use the co-function identity:

We can turn the second term into cosine:

Substitute:

Now, use the sum to product formulas. We will use the following:

Substitute:

Use the even-odd identity:

Therefore:

Replace the second term with the original term:

Proof complete.

the answer to the expression is 83

answer: a. 13/44

step-by-step explanation: judging by the information given to us, we are looking for experimental probability. we can see that 13 males have chosen chocolate ice cream. there are 44 ice creams in total (remember that the total is always the denominator). so our answer is 13/44.