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4 years ago

9

Jacob invested $300 in a savings account and earned $81 in interest at the end of 9 years. What was the interest rate?

1 answer:

ollegr [7]4 years ago

8 0

R = (1/t)(A/P - 1)r = (1/9)((300/81) - 1)Reduce the expression by cancelling the common factors.r=(1/9)(100/27−1)Combine 100/27 and −1 using a common denominator.r=(1/9)(100−1⋅27/27)Simplify the numerator.r=(1/9)(73/27)r = 0.30041152converting r decimal to a percentageR = 0.30041152 * 100 = 30.0412%/yearA. 3%
hope this helps

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3 years ago

At a local restaurant the health inspector visits every 6 days and the fire inspector visits every 8 days

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in this for 8 times 7 is 56 and 42 is for 6 times 7

Step-by-step explanation:

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3 years ago

Tan x tan x + tan x = 0

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Answer:

$x=\pi n, \ \ \ x=\frac{3\pi}{4}+\pi n$

Step-by-step explanation:

We express the angle x in radians for all possible values of x:

$x=\pi n\\\\x=\frac{3\pi}{n}+\pi n$

let tan(x)=u:

$u^2+u=0\\\\u(u+1)=0\\\\u=0,\ u=1$

#Substitute back u=tan(x)

$tan(x)=0 , \ \ \ or \ tan(x)=-1$

#We assign for all values of x

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3 years ago

Let z = 0.3(cos(31°) + i sin(31°)) and w = 20(cos(18°) + i sin(18°)).

Yuliya22 [10]

Answer:

Option (C) is correct.

Step-by-step explanation:

Given that z = 0.3(cos(31°) + i sin(31°)) and 20(cos(18°) + i sin(18°)).

The product of both the complex number is

zw = [0.3(cos(31°) + i sin(31°))] x [20(cos(18°) + i sin(18°))]

=(0.3x20)[cos(31°) x cos(18°) + cos(31°) x i sin(18°) + i sin(31°) x cos(31°)+ i sin(31°) x i sin(18°)]

Here, (0.3x20)=6, is the magnitude of zw, which is stretching of 0.3 by 20.

zw=6[cos(31°) x cos(18°) + i{cos(31°) x sin(18°) + sin(31°) x cos(31°)}+ i² sin(31°)x sin(18°)]

As i²= -1, So

zw=6[cos(31°) x cos(18°) + i{cos(31°) x sin(18°) + sin(31°) x cos(31°)} - sin(31°)x sin(18°)]

=6[{cos(31°) x cos(18°)- sin(31°)x sin(18°)} + i{cos(31°) x sin(18°) + sin(31°) x cos(31°)}]

As cosAcosB - sin A sin B = cos (A+B) and cosAsinB + sin A sos B = sin (A+B), so

zw=6[cos(31°+18°) + i{sin(31°+18°)]

Note that, initially the argument of z is 31° and after rotation of 18° in counterclockwise direction, the argument od zw is 31°+18°= 49°. i.e

zw=6(cos(49°) + isin(49°)).

So, zw can be determined by stretching z by a factor of 20, then rotating by 18° counterclockwise.

Hence, option (C) is correct.

4 0

3 years ago

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