When two electrical resistors with resistance r1 > 0 and r2 > 0 are wired in parallel in a circuit, the combined resistance r, measured in ohms (ω), is given by 1 r = 1 r1 + 1 r2 (a) find ∂r ∂r1 and ∂r ∂r2 after solving for r (e. g., r = . (b) describe how an increase in r1 with r2 held constant affects r. (will r increase or decrease? ) (c) describe how a decrease in r2 with r1 held constant affects r. (will r increase or decrease? )