2cosx=2sin2x. Sin2x is an identity for 2sinxcos. So 2[2sinxcosx] gives you 4sinxcosx. 2cosx=4sinxcosx. Divide 2cosx on both sides and gives you 2sinx=0 and divide again, sinx=0. Sinx is 0 at 0 and 360 degrees, or pi and 2pi. So thats what x would be. 0,360,pi,2pi.
Given:
May:
hamburger: 3.2 pounds * 4.25 = 13.60
hotdogs: 3 packages * 4 = 12
Total cost: 13.60 + 12 = 25.60
June:
hamburger: 3.2 pounds * 1 1/2 = 4.8 pounds * 4.25 = 20.4
hotdogs: 3 packages * 1/3 = 1 package * 4 = 4
Total cost: 20.4 + 4 = 24.4
25.60 - 24.40 = 1.20
They spent more on May by $1.20. Choice C.
x - y = 16
x^2 + x^2 = 130
----------------
x^2 - y^2 = 256
+(x^2 + y^2 = 130)
2x^2 = 386
x^2 = 193
x = <span>13.892 (3DP)
----
</span>x - y = 16
13.892 - y = 16
-y = 2.108
y = -2.108
The numbers are: 13.892 and -2.108
If you’re asking for the answer, it’s 5
