Answer:
Step-by-step explanation:
x because you can see its shape like a sqaue and if you take the sides and fold them it would fold up into a box so put X
Y=kx is the direct variation equation
First plug in the x, y values given to find K
18=k(5)
18/5=k
3.6 = k
Use the k and write a new equation.
y=3.6x
Plug in the x value to solve for y.
y = 3.6(11)
y= 39.6
What? Where’s the question 11
Answer:
X=2
Step-by-step explanation: First 9-7=2 then subtract 2 from both sides and you should be left with X=13
Answer:
cos (
) = ![-\frac{\sqrt{2+\sqrt{2}}}{2}](https://tex.z-dn.net/?f=-%5Cfrac%7B%5Csqrt%7B2%2B%5Csqrt%7B2%7D%7D%7D%7B2%7D)
Decimal value: −0.9238795325...
Step-by-step explanation:
Write,
cos
= cos
= −cos ![\frac{\pi }{8}](https://tex.z-dn.net/?f=%5Cfrac%7B%5Cpi%20%7D%7B8%7D)
Now using half angle formula, cos(x) = 2 cos²(
) − 1, we can write cos
= 2
cos²(
) − 1
This means
+ 1 = 2 cos²(
)
2 cos²(
) = ![\frac{\sqrt{2}+1}{\sqrt{2}}](https://tex.z-dn.net/?f=%5Cfrac%7B%5Csqrt%7B2%7D%2B1%7D%7B%5Csqrt%7B2%7D%7D)
cos²(
) = ![\frac{\sqrt{2}+1}{2\sqrt{2}}](https://tex.z-dn.net/?f=%5Cfrac%7B%5Csqrt%7B2%7D%2B1%7D%7B2%5Csqrt%7B2%7D%7D)
cos(
) = ![\sqrt{\frac{\sqrt{2}+1}{2\sqrt{2}}}](https://tex.z-dn.net/?f=%5Csqrt%7B%5Cfrac%7B%5Csqrt%7B2%7D%2B1%7D%7B2%5Csqrt%7B2%7D%7D%7D)
Simplify,
=
= ![\frac{\sqrt{2+\sqrt{2}}}{2}](https://tex.z-dn.net/?f=%5Cfrac%7B%5Csqrt%7B2%2B%5Csqrt%7B2%7D%7D%7D%7B2%7D)
Hence,
cos (
) = −cos (
) = ![-\frac{\sqrt{2+\sqrt{2}}}{2}](https://tex.z-dn.net/?f=-%5Cfrac%7B%5Csqrt%7B2%2B%5Csqrt%7B2%7D%7D%7D%7B2%7D)