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iOS

Posted by Richard Lu
Richard Lu
20,185 Points

Working with M_PI

Hello friends,

I've been working with some mathematical symbols and something thats occur to me is that M_PI seems to be just a constant with a set precision.

The problem I am having is as follows:

sin(M_PI * 2)   // returns -2.44929359829471E-16  = ~0  SHOULD RETURN 0
sin(M_PI * 3 / 2)   // returns -1
sin(M_PI)   // returns 1.22464679914735E-16 = ~ 0  SHOULD RETURN 0
sin(M_PI/2)   // returns 1

Is there any way to make this more accurate?

agreatdaytocode
agreatdaytocode
24,757 Points

You mean like this:

let π = 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223085334468503526193118817101000313783875288658753320838142061717766914730359825349042875546873115562863882353787593751957781857780532171226806613001927876611195909216420198

So of the people over on stack overflow say to import Darwin have you tried that?

Richard Lu
Richard Lu
20,185 Points

Hey Aaron,

Thanks for the response! I've tried using Darwin, and it gives me the same results. According to some other posts on stack overflow, I shouldn't need the import Darwin since Foundation already includes Darwin (c preprocessors, etc.). I've tried another method which involved conversion into degrees and that was also a deadend.

agreatdaytocode
agreatdaytocode
24,757 Points

Hmm, ok. I'll keep digging and see what I can find :)