Evaluate square root of -13* square root of -5

$\sqrt{- 13} \cdot \sqrt{- 5}$

Step 1

Rewrite $- 13$ as $- 1 (13)$ .

$\sqrt{- 1 (13)} \cdot \sqrt{- 5}$

Step 2

Rewrite $\sqrt{- 1 (13)}$ as $\sqrt{- 1} \cdot \sqrt{13}$ .

$\sqrt{- 1} \cdot \sqrt{13} \cdot \sqrt{- 5}$

Step 3

Rewrite $\sqrt{- 1}$ as $i$ .

$i \cdot \sqrt{13} \cdot \sqrt{- 5}$

Step 4

Rewrite $- 5$ as $- 1 (5)$ .

$i \cdot \sqrt{13} \cdot \sqrt{- 1 (5)}$

Step 5

Rewrite $\sqrt{- 1 (5)}$ as $\sqrt{- 1} \cdot \sqrt{5}$ .

$i \cdot \sqrt{13} \cdot (\sqrt{- 1} \cdot \sqrt{5})$

Step 6

Rewrite $\sqrt{- 1}$ as $i$ .

$i \cdot \sqrt{13} \cdot (i \cdot \sqrt{5})$

Step 7

Multiply $i \sqrt{13} (i \sqrt{5})$ .

Raise $i$ to the power of $1$ .

$i^{1} i \sqrt{13} \sqrt{5}$

Raise $i$ to the power of $1$ .

$i^{1} i^{1} \sqrt{13} \sqrt{5}$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$i^{1 + 1} \sqrt{13} \sqrt{5}$

Add $1$ and $1$ .

$i^{2} \sqrt{13} \sqrt{5}$

Combine using the product rule for radicals.

$i^{2} \sqrt{5 \cdot 13}$

Multiply $5$ by $13$ .

$i^{2} \sqrt{65}$

Step 8

Rewrite $i^{2}$ as $- 1$ .

$- 1 \sqrt{65}$

Step 9

Rewrite $- 1 \sqrt{65}$ as $- \sqrt{65}$ .

$- \sqrt{65}$

Step 10

The result can be shown in multiple forms.

Exact Form:

$- \sqrt{65}$

Decimal Form:

$- 8.06225774 \dots$