write the expression -5i(1 + 3i) as a complex number in standard form.
well, break it up:
-5i : 5@-90
1+3i: sqrt10 @arctan3
now multiply them
5sqrt10 @(-90+71.56) now that angle, after adding 360, is 341.56
5sqrt10 (.9486 -316i)
To write the expression -5i(1 + 3i) as a complex number in standard form, we can perform the multiplication and simplify the expression.
First, let's distribute -5i into the parentheses:
-5i(1 + 3i) = -5i * 1 - 5i * 3i
Simplifying further:
-5i * 1 = -5i
-5i * 3i = -15i^2
Now, we know that i^2 equals -1, so we can substitute that in:
-5i * 1 = -5i
-5i * 3i = -15 * (-1) = 15
Now, let's combine both terms:
-5i + 15
This is the complex number in standard form.