Question

cos x + cos y + cos (x+y) + 1

Answer 1

Isn't that the same as (cosx + cosy)/(cosx + cosy) + 1?

Answer 2

Through the distributive property, the cosine is multiplied with the x and the y.
From crossing out, you will either the answer as
=1

Answer 3

Can u specify more?

Answer 4

Of course. The distributive property shows us that you can multiply anything from the parenthesis. If i multiply cos(x+y) in the parenthesis, I will get cosx + cosy

Answer 5

The result is the numerator staying the same while the denominator changes to cosx + cosy + 1

I then have the same exact two terms on the top and bottom with a + 1
I cancel out the same terms, and am left with +1

Answer 6

cos (x+y) cant be cosx + cosy.
just use the sum formula angles :
cos(x+y) = cosxcosy - sinxsiny

but not sure, how to simply this then ...

Answer 7

More suggestions? Trying to help daugther