Answer:
<em> = n² + 4n ; n = 11 </em>
Step-by-step explanation:
=
[2
+ (n - 1)d]
~~~~~~~~~
= 5
d = 7 - 5 = 2
=
[ 2(5) + 2(n - 1)] =
( 8 + 2n ) = 4n + n²
<em> = n² + 4n</em>
n² + 4n = 165
n² + 4n - 165 = 0
(n + 15)(n - 11) = 0 ( n ≥ 0 ) ⇒ <em>n = 11</em>
I think the answer is B or C
<h3>
Answer: orthogonal </h3>
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Explanation:
For any two vectors defined as follows
u = <a,b>
v = <c,d>
the dot product is computed by
u dot v = a*c + b*d
If the dot product of the vectors is 0, then the vectors are orthogonal. Meaning they are perpendicular to one another.
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Let's find the dot product of these two given vectors
u = < 2, -4 >
v = < 6, 3 >
u dot v = 2*6 + (-4)*3
u dot v = 12 - 12
u dot v = 0
Therefore, these two vectors form a right angle and are <u>orthogonal</u>
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Extra info:
If we can show that u = <a, b> and v = <ka, kb> for some real number k, then we have shown that vectors u and v are parallel.