Math Problem Statement

Simplify the following expression and write in the form a+bi :
1+−81‾‾‾‾√−9‾‾‾√⋅−36‾‾‾‾√

Solution

We are given the expression:

1+819361 + \sqrt{-81} \cdot \sqrt{-9} \cdot \sqrt{-36}

Step 1: Express Square Roots of Negative Numbers in Terms of ii

Using the identity x=ix\sqrt{-x} = i\sqrt{x}, we rewrite each term:

81=i81=i(9)=9i\sqrt{-81} = i\sqrt{81} = i(9) = 9i

9=i9=i(3)=3i\sqrt{-9} = i\sqrt{9} = i(3) = 3i

36=i36=i(6)=6i\sqrt{-36} = i\sqrt{36} = i(6) = 6i

Step 2: Multiply the Terms

Now, compute:

(9i)(3i)(6i)(9i) \cdot (3i) \cdot (6i)

First, multiply the first two terms:

(9i)(3i)=93i2=27i2(9i) \cdot (3i) = 9 \cdot 3 \cdot i^2 = 27i^2

Since i2=1i^2 = -1, we get:

27i2=27(1)=2727i^2 = 27(-1) = -27

Now, multiply by 6i6i:

(27)(6i)=162i(-27) \cdot (6i) = -162i

Step 3: Add 1 to the Result

1+(162i)=1162i1 + (-162i) = 1 - 162i

Final Answer:

1162i\boxed{1 - 162i}

Would you like further clarification or additional examples?

Here are five related problems you might find useful:

  1. Simplify 254\sqrt{-25} \cdot \sqrt{-4}.
  2. Express (2+3i)(4i)(2 + 3i)(4 - i) in the form a+bia + bi.
  3. Find the value of i15i^{15}.
  4. Compute (5i2)2(5i - 2)^2.
  5. Solve for xx in x2+4x+13=0x^2 + 4x + 13 = 0 over complex numbers.

Tip: Remember that i2=1i^2 = -1 and use it to simplify expressions with powers of ii!

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Square Roots
Imaginary Numbers

Formulas

√(-x) = i√x

Theorems

i^2 = -1

Suitable Grade Level

Grades 9-12