Solve -2*frac{2x/sqrt{x^2+4}}{2sqrt{x^2+4}}

$$\frac { - 2 \cdot \frac { 2 x } { \sqrt { x ^ { 2 } + 4 } } } { 2 \sqrt { x ^ { 2 } + 4 } }$$

Evaluate

$$-\frac{2x}{x^{2}+4}$$

Solution Steps

Express -2\times \frac{2x}{\sqrt{x^{2}+4}} as a single fraction.

$$\frac{\frac{-2\times 2x}{\sqrt{x^{2}+4}}}{2\sqrt{x^{2}+4}}$$

Multiply -2 and 2 to get -4.

$$\frac{\frac{-4x}{\sqrt{x^{2}+4}}}{2\sqrt{x^{2}+4}}$$

Express \frac{\frac{-4x}{\sqrt{x^{2}+4}}}{2\sqrt{x^{2}+4}} as a single fraction.

$$\frac{-4x}{\sqrt{x^{2}+4}\times 2\sqrt{x^{2}+4}}$$

Cancel out 2 in both numerator and denominator.

$$\frac{-2x}{\sqrt{x^{2}+4}\sqrt{x^{2}+4}}$$

Multiply \sqrt{x^{2}+4} and \sqrt{x^{2}+4} to get \left(\sqrt{x^{2}+4}\right)^{2}.

$$\frac{-2x}{\left(\sqrt{x^{2}+4}\right)^{2}}$$

Calculate \sqrt{x^{2}+4} to the power of 2 and get x^{2}+4.

$$\frac{-2x}{x^{2}+4}$$

Differentiate w.r.t. x

$$\frac{2\left(x^{2}-4\right)}{\left(x^{2}+4\right)^{2}}$$

Steps Using Derivative Rule for Quotient

Express -2\times \frac{2x}{\sqrt{x^{2}+4}} as a single fraction.

$$\frac{\mathrm{d}}{\mathrm{d}x}(\frac{\frac{-2\times 2x}{\sqrt{x^{2}+4}}}{2\sqrt{x^{2}+4}})$$

Multiply -2 and 2 to get -4.

$$\frac{\mathrm{d}}{\mathrm{d}x}(\frac{\frac{-4x}{\sqrt{x^{2}+4}}}{2\sqrt{x^{2}+4}})$$

Express \frac{\frac{-4x}{\sqrt{x^{2}+4}}}{2\sqrt{x^{2}+4}} as a single fraction.

$$\frac{\mathrm{d}}{\mathrm{d}x}(\frac{-4x}{\sqrt{x^{2}+4}\times 2\sqrt{x^{2}+4}})$$

Cancel out 2 in both numerator and denominator.

$$\frac{\mathrm{d}}{\mathrm{d}x}(\frac{-2x}{\sqrt{x^{2}+4}\sqrt{x^{2}+4}})$$

Multiply \sqrt{x^{2}+4} and \sqrt{x^{2}+4} to get \left(\sqrt{x^{2}+4}\right)^{2}.

$$\frac{\mathrm{d}}{\mathrm{d}x}(\frac{-2x}{\left(\sqrt{x^{2}+4}\right)^{2}})$$

Calculate \sqrt{x^{2}+4} to the power of 2 and get x^{2}+4.

$$\frac{\mathrm{d}}{\mathrm{d}x}(\frac{-2x}{x^{2}+4})$$

For any two differentiable functions, the derivative of the quotient of two functions is the denominator times the derivative of the numerator minus the numerator times the derivative of the denominator, all divided by the denominator squared.

$$\frac{\left(x^{2}+4\right)\frac{\mathrm{d}}{\mathrm{d}x}(-2x^{1})-\left(-2x^{1}\frac{\mathrm{d}}{\mathrm{d}x}(x^{2}+4)\right)}{\left(x^{2}+4\right)^{2}}$$

The derivative of a polynomial is the sum of the derivatives of its terms. The derivative of a constant term is 0. The derivative of ax^{n} is nax^{n-1}.

$$\frac{\left(x^{2}+4\right)\left(-2\right)x^{1-1}-\left(-2x^{1}\times 2x^{2-1}\right)}{\left(x^{2}+4\right)^{2}}$$

Do the arithmetic.

$$\frac{\left(x^{2}+4\right)\left(-2\right)x^{0}-\left(-2x^{1}\times 2x^{1}\right)}{\left(x^{2}+4\right)^{2}}$$

Expand using distributive property.

$$\frac{x^{2}\left(-2\right)x^{0}+4\left(-2\right)x^{0}-\left(-2x^{1}\times 2x^{1}\right)}{\left(x^{2}+4\right)^{2}}$$

To multiply powers of the same base, add their exponents.

$$\frac{-2x^{2}+4\left(-2\right)x^{0}-\left(-2\times 2x^{1+1}\right)}{\left(x^{2}+4\right)^{2}}$$

Do the arithmetic.

$$\frac{-2x^{2}-8x^{0}-\left(-4x^{2}\right)}{\left(x^{2}+4\right)^{2}}$$

Combine like terms.

$$\frac{\left(-2-\left(-4\right)\right)x^{2}-8x^{0}}{\left(x^{2}+4\right)^{2}}$$

Subtract -4 from -2.

$$\frac{2x^{2}-8x^{0}}{\left(x^{2}+4\right)^{2}}$$

Factor out 2.

$$\frac{2\left(x^{2}-4x^{0}\right)}{\left(x^{2}+4\right)^{2}}$$

For any term t except 0, t^{0}=1.

$$\frac{2\left(x^{2}-4\right)}{\left(x^{2}+4\right)^{2}}$$