Evaluate
5-25i
Real Part
5
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-5i\times 5-5i^{2}
Multiply -5i times 5+i.
-5i\times 5-5\left(-1\right)
By definition, i^{2} is -1.
5-25i
Do the multiplications. Reorder the terms.
Re(-5i\times 5-5i^{2})
Multiply -5i times 5+i.
Re(-5i\times 5-5\left(-1\right))
By definition, i^{2} is -1.
Re(5-25i)
Do the multiplications in -5i\times 5-5\left(-1\right). Reorder the terms.
5
The real part of 5-25i is 5.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}