Isoquant

Yield curve yield curve such as an overview of the
(Isoquant)
yield curve is the production of a commodity under the same conditions at the technical level of the two factors of production under certain production inputs of the various combinations of track, on this curve each point represents the proportion of various combinations of input factors, production of which the proportion of each combination can produce are equal.
And the yield curve that can produce a product in a yield level of all possible (efficiency) inputs combination.
1
[Edit this paragraph] the nature of the yield curve, the higher position far away from the origin of such yield curve always represent larger the output
because, generally invest more elements, manufacturers will be able to get a larger output.
2, any two yield curve not intersect
because the same combination of input factors is impossible to produce two different production. The
3, et al yield curve convex to the origin, tilted to the right, the slope of the negative
because every point on the yield curve represents the effective combination of various elements to produce a certain output. Therefore, to increase the amount of some elements of the input and keep output unchanged, it must be a corresponding reduction in the inputs of another factor. If the production yield, the need to increase labor and capital inputs, or does not reduce labor at the same time have to increase the amount of capital, then the original production mix is ​​not valid.
Such as yield curve the type
in accordance with the input elements to the degree of substitution of, to such as the yield curve is divided into three types.
1, between the input factors can substitute
For example, in electricity production, if the power plant boiler fuel can all use the gas can be entirely oil (of course, can also be part of with a gas, some oil) , we call these two kinds of input elements can be replaced. This yield curve shape is a straight line. Alternative to oil ratio, gas, namely replacement rate of 1:1, is a constant.
Such as the production of bicycles, in between the frame and wheels of the input factors can not be substituted completely
2 input elements is not a substitute. This yield curve shape is a right angle lineWorld Steel Pipe . The ratio between the input factors can not substitute for fixed. If the ratio between the frame and wheels for 1:2. The 
this and other yield curve a variant of If an enterprise can use several methods of production to produce the same product, each production method the proportion of input elements are fixed (ie not a substitute for factor inputs), but through different combinations of production methods, still You can change the ratio between the input elements of the entire enterprise. This variant of the yield curve shape is a polyline.
Two workshop production of a product, A workshop level of mechanization, combined with more capital and less labor. Workshop B the low level of mechanization, combined with less capital and more labor. The proportion of each workshop internal input factors is fixedWorld Steel Pipe , but companies assign different tasks across the enterprise to adjust the proportion between the input elements for each workshop. 
of substitution between input factors is the incomplete
such production, the device can replace the labor, but the equipment can not replace all the labor, a case in point. This yield curve shape is generally protruding curve of the original point. So there will be the shape of the input factors can not completely replace them, the slope of the yield curve is generally decrease with the increase of the amount of input factors. Diminishing
yield curve slope descending
yield curve slope, there is an important characteristic for this type of alternative, that is put into the marginal rate of substitution of the elements of X (Marginal Rate of Substitution, MRS) is always with The increase in the amount of X diminishes. The 
if X and Y are two other alternative input factors, then, the marginal rate of substitution of X-X takes a value increase of one unit of input factors X, you can replace the number of units of factor inputs Y-.
Formula: the MRS = ΔY / ΔX. ΔY / ΔX is the slope of yield curve in X takes a value, so, put the marginal rate of substitution of factor X to take a value that is, such as the slope of the yield curve on X takes the value. Since the slope of the yield curve is decreasing, therefore, its marginal rate of substitution is always with the increase of X decreasing, that is, with increasing X in volume, an increase of one unit X best alternative to the The amount of Y, will become increasingly smaller.