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) = 
Answer:
66
Step-by-step explanation:
36x4=144
36x3=78
144-78=66
Answer:
A. -1.6; not significant
Step-by-step explanation:
The z-score of a data set that is normally distributed with a mean of
and a standard deviation of
, is given by:
.
From the question, the test score is:
, the mean is
, and the standard deviation is
.
We just have to plug these values into the above formula to obtain:
.
This simplifies to:
.
.
We can see that the z-score falls within two standard deviations of the mean.
Since
the value is not significant.
The correct answer is A. -1.6; not significant
Check the picture below, recall your SOH, CAH, TOA
The answer is 30
because (2)(10) + 10
20+10=30
the 10 came from the m!!