If Z1 = 12 + 6݅ and Z2 = a + bi (where a, b ∈ R) are two complex number, we can say that the product Z1Z2is imaginary A) If and only if ܽ = ܾ = 0 B) If b = 2a C) If a = −2b D) for each value of a and b

A) if and only if a = 0

Step-by-step explanation:

Since Z1 = 12 + 6݅  and Z2 = a + bi , then the product, Z1Z2 = (12 + 6)(a + bi)

Z1Z2 = (12 + 6)(a + bi)

Expanding the brackets, we have

Z1Z2 = 12a + 12bi + 6a + 6bi

Collecting like terms, we have

Z1Z2 = 12a + 6a + 12bi +6bi

Z1Z2 = 12a + 6a + (12b +6b)i

Simplifying, we have

Z1Z2 = 18a + 18bi

For Z1Z2 to be imaginary, then the real part must be zero.

That is 18a = 0 ⇒ a = 0

So, Z1Z2 is imaginary if and only if a = 0

the equation cos(35) =a/25 can be used to find the length of bc what is the length of bc? round to the nearest tenth

step-by-step explanation:

answer: ratio of volume of cone (with 3 times the height and equal diameter) to volume of cylinder is 2 to 1. the value of π is not used.

step-by-step explanation:

radius is diameter/2 = 4.

area of circle is π r^2.

volume of cylinder is height × area of base = hπr^2 = 3(4^2) π = 48π cubic inches.

not knowing the formula for volume of cone, i calculate it using calculus (which is for calculating things).

volume of cone is integral 0 to h area(y) dy. area(y) is π r(y)^2. r(y) runs r to zero as y runs zero to h, r(0) = r, r(h) = 0.

r(y) = r - r/h y

area(y) = π (r - r/h y)^2 = π (r^2 - 2r^2y/h + r^2y^2/h^2) = π r^2(1-2y/h+y^2/h^2)

antiderivative area(y) = π r^2 (y-y^2/h+y^3/(3h^2))

integral 0 to h = π r^2(h-h^2/h+h^3/(3h^2) - (0)) = π r^2(h - h + h/3) = π r^2(h/3) = π/3 r^2 h

volume of this cone is π/3(4^2)18 cubic inches.

= 6 16 π = 96π cubic inches.

cone has twice the volume, 96/48.

cone height is 6 times the cylinder.

ratio of volume formula: π r^2 cancels.

cone over cylinder ratio is 6h/3 to h, 2 to 1.