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anonymous
 one year ago
Trig question: How to find theta, given X and Y when X and Y are both negative
anonymous
 one year ago
Trig question: How to find theta, given X and Y when X and Y are both negative

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0dw:1437664037564:dw For reference

amistre64
 one year ago
Best ResponseYou've already chosen the best response.0mental gymnasitics ... the trig functions give us an angle in relation to the x axis so we have to make adjustments

amistre64
 one year ago
Best ResponseYou've already chosen the best response.0if given an x and y, it tends to be tan related ..

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0CLARIFICATION: if Y is positive, we can use arccos(x/radius) to find theta, if X is positive, we can use arcsin(y/radius) to find theta Is there an easy way like this to find theta if both are negative? (preferably in very few steps, to make it easy for a computer program to calculate quickly)

freckles
 one year ago
Best ResponseYou've already chosen the best response.1arctan( ) has range pi/2 to pi/2 which means to find theta in the 1st and 4th quadrant we can just do arctan( y/x)+2pi*n I put the +2pi*n depending on the domain of theta n is an integer now the tricky part is what to do when we get to the 2nd and 3rd quadrant if we try doing arctan(y/x) for these two quadrants y/x will be positive if we are in the third quadrant which means arctan(y/x) will really being giving us outputs from the 1st quadrant so we can add pi or even pi+2pi*n or factoring out the pi ... pi(1+2n) something similar happens for the 2nd quadrant dw:1437667271475:dw choosing the integer n depends on the domain of theta
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