Answer:
Expand it.
(1+2i)^3 is equal to (1+2i)(1+2i)(1+2i).
Multiply everything out (being sure to multiply <em>every</em> term. (1+2i) * (1+2i) = 1+2i+2i+4i^2.
i is the square root of negative one, so i^2 is just -1. 1+2i+2i-4 is what you get from the first two, so now simplify that:
1-4 + 2i+2i = (-3+4i) and now multiply that by (1+2i):
(-3+4i) * (1+2i) = -3 - 6i +4i +8i^2.
Simplify again, and the answer is: -11-2i
Step-by-step explanation:
I hope this helps - really my only tip is don't spend time thinking about what i is, that just hurts your brain. Just remember that i^2 is equal to negative one, and treat it like regular multiplication and you will be fine.
Some information is missing for #6.
#7: use sine, sin35=h/5.1, h=5.1*sin35, use a calculator, h≈2.9
#23: to find the reference angle, keep subtracting the number by 360, until the remaining difference is the smallest positive number.
1406-360-360-360=326. the reference angle is 326.
now look at the remainder, the terminal line of 326 degree is in the 4th quadrant between 270 and 360, the the reference angle is 360-326=34, the angle between the terminal line and the positive x axis. 34 is the answer.
lol ok so
7*something or you can make it into a variable x=35
7*x=35
/7 /7
x=5.
