Select the explicit formula for the sequence that correspond to this geometric series: 6 + 18 + 54 + 162 + 486
2 answers:
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The second condition tells you that 
is half the size of 
, so 
, which could be rewritten in several ways. In standard form, that would be 
.
Consider the picture attached.
From right triangle trigonometry:
tan(α)=(opposite side)/(adjacent side)=15/67=0.2239
using a scientific calculator we find that arctan(0.2239)=12.62°
thus α=12.62°, is the angle that the vector makes with the positive x-axis.
The angle made with the + y-axis is 12.62°+90°=102.62°.
The length of the vector v can be determined using the Pythagorean theorem:
Thus, to make v a unit vector, without changing its direction, we need to divide v by |v|=68.8.
This means that the x and y components will also be divided by 68.8, by proportionality.
So, the unit vector in the direction of v is:
<span>(67/68.8)i + (-15/68.8)j=0.97 i + (- 0.22)j
</span>
Answer: 12.62°; 102.62°; 0.97 i + (- 0.22)j
From right triangle trigonometry:
tan(α)=(opposite side)/(adjacent side)=15/67=0.2239
using a scientific calculator we find that arctan(0.2239)=12.62°
thus α=12.62°, is the angle that the vector makes with the positive x-axis.
The angle made with the + y-axis is 12.62°+90°=102.62°.
The length of the vector v can be determined using the Pythagorean theorem:
Thus, to make v a unit vector, without changing its direction, we need to divide v by |v|=68.8.
This means that the x and y components will also be divided by 68.8, by proportionality.
So, the unit vector in the direction of v is:
<span>(67/68.8)i + (-15/68.8)j=0.97 i + (- 0.22)j
</span>
Answer: 12.62°; 102.62°; 0.97 i + (- 0.22)j