Q. A complex number z1 has a magnitude ∣z1∣=4 and an angle θ1=330∘.Express z1 in rectangular form, as z1=a+bi.Express a+bi in exact terms.z1=□
Convert angle to radians: To express a complex number in rectangular form (a+bi) given its magnitude and angle, we use the polar to rectangular conversion formula: z=r(cos(θ)+isin(θ)), where r is the magnitude and θ is the angle in radians. Here, r=4 and θ=330∘.
Calculate radians: First, convert the angle from degrees to radians because the trigonometric functions in the formula require the angle in radians. The conversion formula is radians=degrees×(π/180). So, θ=330×(π/180).
Substitute values into formula: Calculating the radians: θ=330×(π/180)=11π/6 radians.
Calculate trigonometric functions: Now, substitute r=4 and θ=611π into the polar to rectangular conversion formula: z=4(cos(611π)+isin(611π)).
Simplify expression: Calculate cos(611π) and sin(611π). From the unit circle, we know that cos(611π)=23 and sin(611π)=−21.
Simplify expression: Calculate cos(611π) and sin(611π). From the unit circle, we know that cos(611π)=23 and sin(611π)=−21.Substitute the values of cos(611π) and sin(611π) into the formula: z=4(23+i∗(−21)).
Simplify expression: Calculate cos(611π) and sin(611π). From the unit circle, we know that cos(611π)=23 and sin(611π)=−21.Substitute the values of cos(611π) and sin(611π) into the formula: z=4(23+i∗(−21)).Simplify the expression: z=4∗23+4∗(−21)i=23−2i.
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