# TEST HELPsinusoidal- find max and min voltages

• Apr 8th 2013, 02:17 PM
onehundredpercenteffort
TEST HELPsinusoidal- find max and min voltages
This is the question: The voltage from a wall socket can be described by the equation v(t)= 170sin120pit, where t is time, in seconds, and V is the voltage in volts at time t.
1. Find the maximum and minimum voltage levels and the times at which they occur.

• Apr 8th 2013, 02:46 PM
emakarov
Re: TEST HELPsinusoidal- find max and min voltages
Quote:

Originally Posted by onehundredpercenteffort
This is the question: The voltage from a wall socket can be described by the equation v(t)= 170sin120pit, where t is time, in seconds, and V is the voltage in volts at time t.

Is it 170sin(120)pit or 170sin(120pit)? What are p and i? There is no capital V in the equation; there is a lowercase v (in math and physics, those are different things).
• Apr 8th 2013, 03:03 PM
emakarov
Re: TEST HELPsinusoidal- find max and min voltages
Quote:

Originally Posted by onehundredpercenteffort
This is the question: The voltage from a wall socket can be described by the equation v(t)= 170sin120pit, where t is time, in seconds, and V is the voltage in volts at time t.
1. Find the maximum and minimum voltage levels and the times at which they occur.

Ah, I guess the function is $v(t)=170\sin(120\pi t)$. The period of sin(x) is $2\pi$, and multiplying the argument x by some constant a reduces the period a times, i.e., the period of sin(ax) is $2\pi/a$. Now, as with regular sin(x), the maximum of sin(ax) is reached at 1/4 the period and the minimum at 3/4 the period. The maximum and minimum of sin(ax) are 1 and -1, respectively, so the maximum and minimum of b * sin(ax) where b > 0 are b and -b, respectively.