Trigonometry: solve for x: cosx−√3 /4 sin(2x)=0

i got -2/√3 and 2√3 /3.

i don't think i did it right. in advance!

Which of the following is the result of expanding

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

Choco pies are cookies made from chocolate (c), sugar (s), and flour (f). chocolate costs $5 per pound, sugar costs $3 per pound, and flour costs $2 per pound. you spend $50 on 18 pounds of food and buy twice as much flour as sugar. calvin wants to invest $12,000 in deposits. for tax purposes, he wants his total interest to be $600. he wants to put $1000 more in a 2-year deposit than in a 1-year deposit and invest the rest in a 3-year deposit. how much money should he invest in each deposit?