Consider the complex number z=8(cos(240∘)+isin(240∘)). Which of the following complex numbers best approximates z ?Choose 1 answer:(A) 6.9−4i(B) −6.9−4i(C) −4−6.9i(D) 4−6.9i
Q. Consider the complex number z=8(cos(240∘)+isin(240∘)). Which of the following complex numbers best approximates z ?Choose 1 answer:(A) 6.9−4i(B) −6.9−4i(C) −4−6.9i(D) 4−6.9i
Convert to trigonometric form: Convert the given complex number in trigonometric form to standard form.We have z=8(cos(240°)+isin(240°)). To convert this to standard form, we need to evaluate the cosine and sine of 240°.
Calculate cosine and sine: Calculate the cosine and sine of 240°. The angle 240° is in the third quadrant, where cosine is negative and sine is also negative. We can use the reference angle of 240°−180°=60° to find the values. cos(240°)=−cos(60°)=−21sin(240°)=−sin(60°)=−23
Substitute values into complex number: Substitute the values of cosine and sine into the complex number. z=8(−21+i(−23))z=8×−21+8×i(−23)z=−4−4i3
Approximate imaginary part: Approximate the value of 3 to find the imaginary part of z.3 is approximately 1.732. So, the imaginary part of z is:−4i3≈−4i×1.732≈−6.928i
Write in standard form: Write the complex number in standard form with the approximated values. z≈−4−6.928i
Compare with options: Compare the approximated complex number with the given options.The approximated complex number is −4−6.928i. The option that best matches this number is (C) −4−6.9i.
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