Sin2(x) +cos(x)=1
from the relation: (sin2(x) +cos2(x) =1 )
so , sin2(x)=1-cos2(x)
by subs. in the main eqn.
1-cos2(x) + cos(x) =1
by simplify the eqn.
cos(x) -cos2(x)=0
take cos(x) as a common factor
cos(x)* (1-cos(x))=0
then cos(x)=0 && cos(x)=1
cos(x)=0 if x= pi/2
& cos(x) = 1 if x = 0 , 2*pi
so the solution is x= {0,pi/2 , 2*pi}

3 0

3 years ago

The credit remaining on a phone card (in dollars) is a linear function of the total calling time made with the card (in minutes)

saw5 [17]

Answer: $19.6

Step-by-step explanation:

Linear function: f(x)=mx+c

, where m= rate of change in f(x) with respect to x.

c = Initial value.

Let c = Initial value of card , m= Charge per minute

x= Number of minutes calling time.

Then, 25.06= 38m+c (i)

21.03=69m+c (ii)

Eliminate (ii) from (i)

$4.03=-31m\\\\\Rightarrow\ m=\dfrac{4.03}{-31}\\\\\Rightarrow\ m=-0.13$

Put m in (i) , we get

$25.06= 38(-0.13)+c\\\\\Rightarrow\ 25.06=-4.94+c\\\\\Rightarrow\ c=25.06+4.94\\\\\Rightarrow\ c=30$

i.e. f(x)=-0.13x+30

if x=80 then

f(80)= -0.13(80)+30

=-10.4+30

=19.6

Hence, the remaining credit after 80 minutes of calls = $19.6

7 0

3 years ago

Which expression was factored completely using the GCF, if the original expression was

Lerok [7]

Answer:

4x(x+2)

Step-by-step explanation:

4 0

3 years ago

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