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Why is the absolute value of a plus B equal to the absolute value of a minus B when a is perpendicular to B,
|a+b|^2 = |a|^2+|b|^2+ 2a.b
|a-b|^2 = |a|^2+|b|^2- 2a.b
|a+b|=|a-b|
=> a.b =0
=>A vertical B
Sina times cosa
sina*cosa=(2sina*cosa)/2=sin(2a)/2
What is cosa Sina = if sina is multiplied by cosa = 1 / 8?
sinacosa=1/8
2sinacosa=1/4
-2sinacosa=-1/4
1-2sinacosa=-1/4+1
cos²a-2sinacosa+sin²a=3/4
(cosa-sina)²=3/4
cosa-sina=±√3/2
The relationship between Sina times Sina and cosa
sina*sina=sin^2a=1-cos^2a
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