Describe how you would convince a friend that sin(x + y) does not equal sin x + sin y.

If the claim is that for all , then all you need to refute it is a single example for which the equality doesn't hold. Take . Then , but .

If the claim is that there is some choice of for which equality holds, then we can recall the angle sum identity for sine:



which means that, in order to have equality, we need to choose such that both and . We can do that; only when is an even multiple of , i.e. . Take any two of these and add them together, and you'd end up with yet another even multiple of , and so both sides will reduce to 0. Thus equality holds only when and for some integers .

Trigonometry functions

In order to convince a friend that  sin(x + y) does not equal sin x + sin y, we can assume a value for the angle "x and "y"

Let;

x = 30 degreesy = 30 degrees

Substitute the given values into sin(x+y) and sinx + siny

sin(x+y) = sin(30+30) = sin60

sin 60 = 0.8660

For sinx + siny

sin x + sin y = sin 30 + 30

sinx  + sin y = 0.5 + 0.5 = 1

Since 0.8660 ≠ 1.0, hence sin(x + y) does not equal sin x + sin y.

Learn more on trig. functions here: link

The answer is c because you turn 17.5% into a decimal which gives you .175 then you times that by $361.35 which gives you 63.23625 but then you round that which gives you 63.24. then you at 63.24 pulse 361.35 and you round it which gives you $425

Cdoes not have two variables