HP-34C

thumb|right|300px|upright|HP-34C Calculator The HP-34C continuous memory calculator is an advanced scientific programmable calculator of the HP 30 series. It was produced between 1979 (cost US$150) and 1983 (cost US$100).

== Features == === Root-finding and integration === Significant to the HP-34C calculator is the capability for integration and root-finding (a first for any pocket calculator). Integration and root-finding works by having the user input a formula as a program. Multiple roots are found using the technique of first finding a root x=x_0, then dividing the equation by (x-x_0), thus driving the solution of the equation away from the root at that point. This technique for multiple root-finding is referred to as "deflation". The user would usually programmatically recall the root value from a storage register to improve its precision.