First we use sin(a+b)= sinacosb+sinbcosa
and cos(a+b)=cosa cosb -sinasinb
tan(x+pi/2)= sin(x+pi/2) / cos(x+pi/2)
and sin(x+pi/2) = sinxcospi/2 + sinpi/2cosx =cosx,
<span>cos(x+pi/2) = cosxcospi/2- sinxsinpi/2= - sinx,
</span> because <span>cospi/2 =0, </span>and <span>sinpi/2=1
</span><span>=tan(x+pi/2)= sin(x+pi/2) / cos(x+pi/2)= cosx / -sinx = -1/tanx = -cotx
</span>from where <span>tan(x+pi/2)=-cotx</span>
If Marita has one dime, she has 0.10 = 1/10 dollars. If she has "x" times that many dimes, she has 0.10x = x/10 dollars (in dimes).
The only answer choice containing this term is ...
( A ) x/10 + 0.75 + 10y
Answer:
Yvette cleared 10 large driveways
Step-by-step explanation:
small driveway = x
big driveway = y
x+y = 25
15x + 25y = 475
y = 25-x
15x + 25(25-x) = 475
-10x + 625 = 475
10x = 150
x= 15
15 + y = 25
y =10
10 large driveways, 1 5 small driveways
