Answer:
13 it is very easy
Step-by-step explanation:
T=-1
sinA=sin(π/2-3A), A=2nπ+π/2-3A, 4A=2nπ+π/2, A=nπ/2+π/8 where n is an integer.
Also, π-A=2nπ+π/2-3A, 2A=2nπ-π/2, A=nπ-π/4.
The hard way:
cos3A=cos(2A+A)=cos(2A)cosA-sin(2A)sinA.
Let s=sinA and c=cosA, then s²+c²=1.
cos3A=(2c²-1)c-2c(1-c²)=c(4c²-3).
s=c(4c²-3) is the original equation.
Let t=tanA=s/c, then c²=1/(1+t²).
t=4c²-3=4/(1+t²)-3=(4-3-3t²)/(1+t²)=(1-3t²)/(1+t²).
So t+t³=1-3t², t³+3t²+t-1=0=(t+1)(t²+2t-1).
So t=-1 is a solution.
t²+2t-1=0 is a solution, t²+2t+1-1-1=0=(t+1)²-2, so t=-1+√2 and t=-1-√2 are solutions.
Therefore tanA=-1, -1+√2, -1-√2 are the three solutions from which:
A=-π/4, π/8, -3π/8 radians and these values +2πn where n is an integer.
Replacing π by 180° converts the solutions to degrees.
Answer: The value of the stove after 5 years is $1121.54
Step-by-step explanation:
Given: The price of stove A= $1150
The price depreciates about 0.5% each year.
In decimal the rate of depreciation r= 0.005
The value of the stove after x years is given by
The value of the stove after 5 years is given by
Hence, The value of the stove after 5 years is $1121.54.
(3x +4) + (6x + 5) = 90*
*note that complementary = 90, supplementary = 180
9x + 9 = 90
9x = 90 - 9
9x/9 = 81/9
x = 9
hope this helps
Answer:
13
Step-by-step explanation:
IT IS 13 ITS IS 13 IT IS 13
