21 in a parallel circuit current moves through multiple

Question

21.) In a parallel circuit, current moves through multiple paths. That means two resistors that are wired in parallel circuits have a lower total resistance than either of the parallel resistors. So, if you know what the smaller resistor is, then as the other resistor gets larger, the total resistance will never be larger than the smallest resistance in the circuit. It has a limit.

The formula for resulting resistance, R_T, (the combined resistance) of two resistors in a parallel

circuit, one R₁ and the other R₂ is Rt= R1R2/R1/R2 

. a.) If R₁ is 10 Ω, find the limit of R_T as R_{2 approaches} ∞.

b.) Find R_T for R₁ = 10 and R₂ = 5

c.) Find R_T for R₁ = 10 and R₂ = 250

d.) Given b.) and c.) above, will R_T ever go above 10 ? Explain why. 

22.) Give the formula for the slope of a straight line and then the formula for the slope of a curve. How are the formulas the alike ? How are they different ?