9514 1404 393
Answer:
25 +0i
Step-by-step explanation:
The conjugate of a complex number is that number with the sign of the imaginary part reversed.
For z = -3+4i, its conjugate z* is -3-4i. The product of z and z* is ...
(-3 +4i)(-3 -4i) = -3(-3 -4i) +4i(-3 -4i)
= 9 +12i -12i -16i² = 9 +16 = 25
The real part of the product is 25; the imaginary part is 0.
(-3 +4i)(-3 -4i) = 25 +0i
_____
You may have noticed that (z)(z*) = |z|², the sum of the squares of the real and imaginary parts. It is always a non-negative real number.
Answer:
see explanation
Step-by-step explanation:
The hypotenuse is the longest side thus is (4x + 1)
The legs are 2x and (4x - 1)
Using Pythagoras' theorem, then
(4x + 1)² = (2x)² + (4x - 1)² ← expanding factors
16x² + 8x + 1 = 4x² + 16x² - 8x + 1 , that is
16x² + 8x + 1 = 20x² - 8x + 1 ( subtract 20x² - 8x + 1 from both sides )
- 4x² + 16x = 0 ( multiply through by - 1 )
4x² - 16x = 0 ← factor out 4x from each term
4x(x - 4) = 0
Equate each factor to zero and solve for x
4x = 0 ⇒ x = 0
x - 4 = 0 ⇒ x = 4
Now x > 0, thus x = 4
2x = 2(4) = 8
4x - 1 = 4(4) - 1 = 16 - 1 = 15
4x + 1 = 4(4) + 1 = 16 + 1 = 17
Thus
perimeter = 8 + 15 + 17 = 40 cm
