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A complex number 
z_(1) has a magnitude 
|z_(1)|=7 and an angle 
theta_(1)=158^(@).
Express 
z_(1) in rectangular form, as 
z_(1)=a+bi.
Round 
a and 
b to the nearest thousandth.

z_(1)=◻+◻i

A complex number z1 z_{1} has a magnitude z1=7 \left|z_{1}\right|=7 and an angle θ1=158 \theta_{1}=158^{\circ} .\newlineExpress z1 z_{1} in rectangular form, as z1=a+bi z_{1}=a+b i .\newlineRound a a and b b to the nearest thousandth.\newlinez1=+i z_{1}=\square+\square i

Full solution

Q. A complex number z1 z_{1} has a magnitude z1=7 \left|z_{1}\right|=7 and an angle θ1=158 \theta_{1}=158^{\circ} .\newlineExpress z1 z_{1} in rectangular form, as z1=a+bi z_{1}=a+b i .\newlineRound a a and b b to the nearest thousandth.\newlinez1=+i z_{1}=\square+\square i
  1. Convert to Radians: To convert a complex number from polar to rectangular form, we use the formulas a=rcos(θ)a = r \cdot \cos(\theta) and b=rsin(θ)b = r \cdot \sin(\theta), where rr is the magnitude and θ\theta is the angle in radians.
  2. Calculate Real Part: First, we need to convert the angle from degrees to radians because the trigonometric functions in most calculators use radians. The conversion is done by multiplying the angle in degrees by π/180\pi/180. \newlineθ1\theta_{1} in radians = 158×(π/180)158 \times (\pi/180).
  3. Calculate Imaginary Part: Now we calculate the real part aa of the complex number z1z_{1} using the cosine function.a=z1cos(θ1)=7cos(158(π/180)).a = |z_{1}| \cdot \cos(\theta_{1}) = 7 \cdot \cos(158 \cdot (\pi/180)).
  4. Perform Calculations: Next, we calculate the imaginary part bb of the complex number z1z_{1} using the sine function.b=z1sin(θ1)=7sin(158(π/180)).b = |z_{1}| \cdot \sin(\theta_{1}) = 7 \cdot \sin(158 \cdot (\pi/180)).
  5. Round to Nearest Thousandth: Perform the calculations for aa and bb using a calculator.\newlinea7×cos(158×(π/180))7×cos(2.7596)6.848.a \approx 7 \times \cos(158 \times (\pi/180)) \approx 7 \times \cos(2.7596) \approx -6.848.\newlineb7×sin(158×(π/180))7×sin(2.7596)1.913.b \approx 7 \times \sin(158 \times (\pi/180)) \approx 7 \times \sin(2.7596) \approx 1.913.
  6. Round to Nearest Thousandth: Perform the calculations for aa and bb using a calculator.\newlinea7×cos(158×(π/180))7×cos(2.7596)6.848.a \approx 7 \times \cos(158 \times (\pi/180)) \approx 7 \times \cos(2.7596) \approx -6.848.\newlineb7×sin(158×(π/180))7×sin(2.7596)1.913.b \approx 7 \times \sin(158 \times (\pi/180)) \approx 7 \times \sin(2.7596) \approx 1.913.Round aa and bb to the nearest thousandth.\newlinea6.848a \approx -6.848 rounded to 6.848.-6.848.\newlineb1.913b \approx 1.913 rounded to 1.913.1.913.

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