Production function with two factor input or production function with ISO-Quants & ISO-Costs

In the long run supply of both the inputs can be varied. With larger employment of labour and capital, the scale of production increases. But sometimes any combination of two factor inputs will result with the same production or output. This can be represented with the help of a diagram. In the adjacent diagram, as we can see, the producer can select X, Y or Z combination of labour and capital. If manufacturer selects X combination, then he would be using 6 units of capital and 4 labourers. Similarly if he selects combination Y, then he would be using 4 units of capital and 6 labourers and likely in Z combination, he would be using 2 units of capital and 8 labourers. Any of these combination, the final output is 100.

Hence, those combination of two factors, which results with the same output, joined with the help of a curve, results with ISO-Quant curve. ISO means Equal and QUANT means quantity. So it is also known as Equal Quantity curve, because any point on the Iso-Quant curve results with the same level of output.  