Last 2
|dw:1527827868649:dw| just the first line
would the 4 apply to the cos or isin?
|dw:1527828022755:dw|
4 is the r value, it has nothing to do with the cos and sin values
okay so do I cube the entire equation?
you are given [r(cos(theta) + isin(theta)]^n identify your r, theta, and n values, then write your solution in the form r^n * (cos(n*theta) + i sin(n*theta))
cos(7pi/9)+isin(7pi/9)^3
now identify what your r, n, and theta are
r=4 n=3 theta=7pi/9
good, so r^n * (cos(n*theta) + i sin(n*theta)) = ?
r^n * (cos(n*theta) + i sin(n*theta)) 4^3*(cos(3*7pi/9)+isin(3*7pi/9))
good it wants the solution in standard form so you just need to distribute the 4^3 and use your calculator to evaluate the costheta and sintheta values to get something in the form a + bi
64(1/2+(i)sqrt3/2)
good but distribute that 64
32+32isqrt3
good but as a minor change it wants the solution in a +bi form so 32 + 32sqrt(3)i
then go through the same steps for 17
okay same thing ofr the next
okay will be back in a few
cos(72)+isin(72)^5 r=1/2 n=5 theta=72 r^n * (cos(n*theta) + i sin(n*theta)) = 1/2^5*(cos(5*72)+isin(5*72)) 1/32
good now convert to a + bi form
1+32i?
what are cos(5*72) and sin(5*72) = ?
1 and 0
good so putting it together gives us 1/32 + 0i
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