The DrawInv Command

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Command Summary

Draws the inverse of a curve in terms of X.

Command Syntax

DrawInv curve

Menu Location

Press:

1. 2nd DRAW to access the draw menu.
2. 8 to select DrawInv, or use arrows and ENTER.

Calculator Compatibility

TI-83/84/+/SE

Token Size

1 byte

The DrawInv command draws the inverse of a curve in terms of X. Its single argument is an expression in terms of X.

For example, DrawInv X² will draw the inverse of the equation Y=X². The inverse reverses the variables X and Y, so that the curve X=Y² will be graphed. In this case, the inverse of the function has a simple form: Y=√(X) and Y=-√(X); most functions, however, do not have an inverse expressible as Y= equation, making this command particularly useful.

You can also think of this as graphing the expression but with X representing the vertical direction, and Y representing the horizontal.

DrawInv requires the calculator to be in Func mode, and is affected by the Connected/Dot setting.

Advanced Uses

DrawInv will update X and Y for each coordinate drawn (like Tangent( and DrawF), and exit with the last coordinate still stored.

When evaluating the expression using DrawInv, the calculator will ignore the following errors: ERR:DATA TYPE, ERR:DIVIDE BY 0, ERR:DOMAIN, ERR:INCREMENT, ERR:NONREAL ANS, ERR:OVERFLOW, and ERR:SINGULAR MAT. If one of these errors occurs, the data point will be omitted.

For this reason, DrawInv can sometimes behave in an unexpected fashion: for example, it doesn't throw an error for list or matrix expressions (it won't graph anything, either).

Error Conditions

• ERR:MODE is thrown if the calculator is not in Func mode when using DrawInv.

Related Commands

• DrawF
• Tangent(

.