Thursday, 19 November 2015

trigonometry - Finding a solution to sin(x) = -5 using Euler's Formula



I have just learned about Euler's formula and I am attempting to find a solution to sin(θ)=5. However, I am not entirely sure how to precede.




Thank You So Much!


Answer



HINT (you only need to simplify the final answer):



sin(x)=5


12(ieixieix)=5

ieixieix=10







Substitute y=ieix:






1(0i)e(0+i)x+(0i)e(0+i)x=10


y+1y=10

y2+1y=10

y2+1=10

y2+10y+1=0

y2+10y=1


y2+10y+25=24

(y+5)2=24

y+5=±24

y+5=±26

y=±265

ieix=±265

eix=±265i

ix=ln(±265i)+2iπn

x=ln(±265i)+2iπni


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