4. The speed of a d. c. motor increases with increasing current through the armature coil. Given fixed supply voltage, two ways of changing the current supplied to the motor are: (1) a variable resistor (potentiometer) or (2) pulse width modulation (PWM). Explain how each method works. Provide one advantage and one disadvantage of each method.

c

explanation:

i believe the answer is c and this is only worth 10 points you might wanna change it

i think it because equal matrices have equal dimensions, only square matrices can be symmetric. for all indices and . every square diagonal matrix is symmetric, since all off-diagonal elements are zero. in linear algebra, a real symmetric matrix represents a self-adjoint operator over a real inner product space.

because growing process had stoped after 4-5 year