Answer:
C) 
Step-by-step explanation:
By the cos double angle formula, we know 
Substituting 
into the formula, we get
.
The answer is C.
Answer:
do you have a picture
Step-by-step explanation:
<span>We have lateral faces that are rectangles and 2 congruent polygons that are bases. This must be 3-dimensional solid figure - quadrilateral prism. If those 2 bases are squares then it is a rectangular prism, but the bases also can be 2 rhombuses. Answer: Quadrilateral prism.</span><span />
Answer:
8 and 10
Step-by-step explanation:
First, let's look at the factors of 80.
1 • 80 = 80
2 • 40 = 80
4 • 20 = 80
5 • 16 = 80
8 • 10 = 80
Look at each pair and evaluate their sum.
1 • 80 = 80
2 • 40 = 80
4 • 20 = 80
5 • 16 = 80
8 • 10 = 80
Our last pairing multiplies to 80 and adds up to 18. Therefore, your answer is 8 & 10.
Hope this helps!
1.No error , he divided by 16 in the 2 sides .
2.no error ,he made sure that 16/16 is one while d/16 remains
3.no error , he square rooted both sides
4.error, as the root gives one positive value and one negative value not only a positive value ,the answer should have been t=+-(d/4)
5.error,he disturbed the whole equation by rooting d only he should have rooted both sides
