Answer:
We cannot infer at the 10% significance level that the assumption of ski centers is wrong
Step-by-step explanation:
The null hypothesis for this question can be stated as
Null hypothesis H0: =4
Alternate hypothesis Ha:
The test is two tailed
Standard Deviation –
= 2
z=(4.84-4)/(2/sqrt(63))
=3.33
Z(0.1/2)=1.645 is less than Z =3.334
Hence, we will reject H0
Hence, the average growth skier ski’s four times a year is not true
I used a triangle generator, see picture attached
Answer:

Step-by-step explanation:
Using the addition formulae for cosine
cos(x ± y) = cosxcosy ∓ sinxsiny
---------------------------------------------------------------
cos(120 + x) = cos120cosx - sin120sinx
= - cos60cosx - sin60sinx
= -
cosx -
sinx
squaring to obtain cos² (120 + x)
=
cos²x +
sinxcosx +
sin²x
--------------------------------------------------------------------
cos(120 - x) = cos120cosx + sin120sinx
= -cos60cosx + sin60sinx
= -
cosx +
sinx
squaring to obtain cos²(120 - x)
=
cos²x -
sinxcosx +
sin²x
--------------------------------------------------------------------------
Putting it all together
cos²x +
cos²x +
sinxcosx +
sin²x +
cos²x -
sinxcosx +
sin²x
= cos²x +
cos²x +
sin²x
=
cos²x +
sin²x
=
(cos²x + sin²x) = 