Since sin(2x)=2sinxcosx, we can plug that in to get sin(4x)=2sin(2x)cos(2x)=2*2sinxcosxcos(2x)=4sinxcosxcos(2x). Since cos(2x) = cos^2x-sin^2x, we plug that in. In addition, cos4x=cos^2(2x)-sin^2(2x). Next, since cos^2x=(1+cos(2x))/2 and sin^2x= (1-cos(2x))/2, we plug those in to end up with 4sinxcosxcos(2x)-((1+cos(2x))/2-(1-cos(2x))/2)
=4sinxcosxcos(2x)-(2cos(2x)/2)=4sinxcosxcos(2x)-cos(2x)
=cos(2x)*(4sinxcosx-1). Since sinxcosx=sin(2x), we plug that back in to end up with cos(2x)*(4sin(2x)-1)
Letter A is the answer to your equation problem
Answer:
32.98 ft
Step-by-step explanation:
What you have right there is a triangle.
The base of the triangle is given (14 ft)
The angle from the ladder makes while leaning on the house is 67 degrees.
This is a simple trigonometry problem
You want to find the length of the ladder and you don't have the hypotenuse
So you can use the function tan to find it.
tan(Ф) = opposite/adjacent
You are looking for the opposite side length
So you do tan(Ф) * adjacent = opposite
tan(67) * 14 = 32.98 ft
Answer:
C
Step-by-step explanation:
In 7 years, Jose will be his age + 7 years.
