Cos( A + B ) = cosAcosB - sinAsinB ;
cos( A + B ) / ( cosAsinB ) = ( cosAcosB - sinAsinB ) / ( cosAsinB ) = ( cosAcosB ) / ( cosAsinB ) - ( sinAsinB ) / ( cosAsinB ) = cosB / sinB - sinA / cosA = cotB - tanA ;
First you need to find the slope, which is (y2-y1)/(x2-x1)
Plug the points in as (1-4)/(-1-1) -> -3/-2
The slope is 3/2, or 1.5
Point slope form is y-y1 = m(x-x1)
Plug in the slope (m) and the first point
y-4 = 1.5(x-1) <-- That's point slope form
To get standard form (ax+by=c), you can use point slope form
y - 4 = 1.5(x - 1)
y - 4 = 1.5x - 1.5
y = 1.5x + 2.5
-1.5x + y = 2.5 <-- Standard Form
Answer:
Step-by-step explanation:
She writes 180words in 5min
In 1 min she writes = 180/5 words
= 36 words
In 1hr = 60min she will write = 36×60words
= 2160words
: she will write 2160words in 1hr
A=1/10, b=1/12, c=1/15 (these are the rates for each worker...)
1.)
2(1/10)+4(1/12)+t/15=1
1/5+1/3+t/15=1
(3+5+t)/15=1
3+5+t=15
8+t=15
t=7
So it would take c 7 hours to finish the job.
2.)
1/40-1/60
(3-2)/120
1/120
The drain rate is 1/60. So you will need to find t when the tank is empty, while starting at 2/3 capacity...
2/3-t/60=0
(40-t)/60=0
40-t=0
t=40
It would take 40 minutes to empty the tank when it is 2/3 full.
