Answer:
D
Step-by-step explanation:
(cos t) (sec t − cos t)
1 − cos² t
sin² t
A is the correct answer
(to find diagonal of a square , you can get help from Pythagorean Theorem)
good luck
Answer:
Step-by-step explanation:
Let older brother age be x and the age difference between the brothers be y
Younger brother's current age = x - y
When older brother's age was at x - y, younger brother's age was x - 2y = 2
When young brother's age will be at x, older brother's age will be x + y = 20
Subtracting the first equation from the second: 3y = 18
y = 6
x = 14
So the older brother is 14 and the younger brother is 8.
Sum of three son's ages now = 15 + 11 + 7 = 33
Daddy's age now = 45
Age difference = 12
Each year, daddy's age goes up by 1 while the sum of three son's ages goes up by 3.
Dividing the age difference by the difference in age gain, 12 / (3 -1) = 12 / 2
= 6
So in 6 years when daddy is 51 and the sum of sons at 21, 17 and 13 will be equal.