Answer:
steps below
Step-by-step explanation:
Are you going to solve the value of A or just a proof the equation
cos 2A = cos² A - sin² A
2cos²A-cos2A-1 = 2cos²A - (cos² A - sin² A) - 1 = cos² A + sin² A - 1
2cos²A-cos2A-1 = 1 - 1 = 0
A: 90° or 270° or 450° .....
let
x----------> number of square jam sandwiches of Ken in the
side x of rectangle
y---------> number of square jam sandwiches of Ken in
the side y of rectangle
A1-------------> total number of square jam sandwiches of
Ken
A2-------------> total number of square jam sandwiches of Sara
we know that
A1=xy
A2=[(x+2)(y+2)-xy]
A1=A2
xy=[(x+2)(y+2)]-xy------------
> xy=xy+2x+2y+4-xy
xy-2y=2x+4-------- > y=[2x+4]/[x-2]
testing different values of x to get a pair of whole numbers-->
see the table attached I find 2 solutions
<span>1) x=3 and y=10
</span>A1=3*10=30
A2=30<span>
total number of sandwiches of Ken------ > 30
</span>total number of sandwiches of Sara------ > 30
<span>
2) <span>x=4 and y=6
</span></span>A1=4*6=24
A2=24<span>
total number of sandwiches of Ken------ > 24
</span><span>total number of sandwiches of Sara------ >24</span>
Add 5 to the side with -5 so it cancels out the -5. Move the positive 5 to the side with 4. Your equation is h = 4+5. Take 4+5 to get 9 and your equation is h=9. :)
Hundredths: 8.98
Tenths: 9 whole
ones: 9 whole
tens: there is none