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>
Answer:
1) one solution
2) Infinitely many solution
3) no solution
Step-by-step explanation:
The first equation is -14-8x=-2(-3x+7)
Let us expand the right hand side to get:
-14-8x=-2*-3x+-2*7
We multiply -14-8x=6x-14
We group similar terms to get:
-8x-6x=-14+14
Combine similar terms to get:
-14x=0
Divide through by -14 to get:
x=0
2) The second equation is 3+5x=5(x+2)-7
We expand to obtain:
3+5x=5x+5*2-7
Multiply to get:
3+5x=5x+10-7
This gives us
3+5x=5x+3
5x=5x
1=1
There is infinitely many solutions
3) The third equation is: 36-7x=-7(x-5)
We expand to get:
36-7x=-7x+35
Group similar terms;
-7x+7x=35-36
0=-1
This statement is not true so there is no solution.
36 inches is equal to 3 feet ;)
Answer:
1/4, 3/8, 2/3
Step-by-step explanation:
3/8 is more than 25% (1/4) but is less than 66% (2/3) making the order 1/4 3/8 2/3.
