-7 is the missing exponent
very simple, we use the formula sin(a+b)=sinacosb +
sinbcosa and sin(20)=2sinacosa
5pi = 2pi/3+3pi/3,
First, we use sin(a+b)=sinacosb + sinbcosa
sin(5pi/3)=sin(2pi/3+3pi/3)=
sin(2pi/3+pi)=
sin(2pi/3)cos(pi) +sin(pi)cos(2pi/3)
but we know that sin(pi)=
0, and cos (pi) = -1, so sin(5pi/3)=
- sin(2pi/3)
now, use sin(2a)=2sinacosa,
sin(5pi/3)= - sin(2pi/3)= -2sin(pi/3)cos(pi/3)
sin<span>(5pi/3)=
-2sin(pi/3)cos(pi/3)</span>
<span>sin(pi/3)= 0.86,
cos(pi/3)=0.5, finally we have </span>sin<span>(5pi/3)= -0.86 x 0.5= -0.43</span>
Answer:
% Po lost = 100[1 - e^(-0.005t)] %; 73.0 g
Step-by-step explanation:
p(t) = 100e^(-0.005t)
Initial amount: p(0) = 100
Amount remaining: p(t) = 100e^(-0.005t)
Amount lost: p(0) – p(t) = 100 - 100e^(-0.005t) = 100[1 - e^(-0.005t)]
% of Po lost = amount lost/initial amount × 100 %
= [1 - e^(-0.005t)] × 100 % = 100[1 - e^(-0.005t)] %
p(63) = 100e^(-0.005 × 63) = 100e^(-0.315) = 100 × 0.730 = 73 g
The mass of polonium remaining after 63 days is 73 g.
