Evaluate
-\frac{a+4}{2\left(a^{2}-4\right)}
Factor
-\frac{a+4}{2\left(a^{2}-4\right)}
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\frac{1}{4}\times \frac{2a}{a^{2}-4}-\frac{1}{a-2}
Multiply \frac{1}{4} and 1 to get \frac{1}{4}.
\frac{2a}{4\left(a^{2}-4\right)}-\frac{1}{a-2}
Multiply \frac{1}{4} times \frac{2a}{a^{2}-4} by multiplying numerator times numerator and denominator times denominator.
\frac{a}{2\left(a^{2}-4\right)}-\frac{1}{a-2}
Cancel out 2 in both numerator and denominator.
\frac{a}{2\left(a-2\right)\left(a+2\right)}-\frac{1}{a-2}
Factor 2\left(a^{2}-4\right).
\frac{a}{2\left(a-2\right)\left(a+2\right)}-\frac{2\left(a+2\right)}{2\left(a-2\right)\left(a+2\right)}
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of 2\left(a-2\right)\left(a+2\right) and a-2 is 2\left(a-2\right)\left(a+2\right). Multiply \frac{1}{a-2} times \frac{2\left(a+2\right)}{2\left(a+2\right)}.
\frac{a-2\left(a+2\right)}{2\left(a-2\right)\left(a+2\right)}
Since \frac{a}{2\left(a-2\right)\left(a+2\right)} and \frac{2\left(a+2\right)}{2\left(a-2\right)\left(a+2\right)} have the same denominator, subtract them by subtracting their numerators.
\frac{a-2a-4}{2\left(a-2\right)\left(a+2\right)}
Do the multiplications in a-2\left(a+2\right).
\frac{-a-4}{2\left(a-2\right)\left(a+2\right)}
Combine like terms in a-2a-4.
\frac{-a-4}{2a^{2}-8}
Expand 2\left(a-2\right)\left(a+2\right).
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Simultaneous equation
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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}