HP 15c Scientific Example:, X-Register, Clearing the Real, Clearing a Complex Number

Section 11: Calculating With Complex Numbers 125

of Complex mode. Instead, you can do either of the following:

∙Multiply by -1.

∙If you don't want to disturb the rest of the stack, press “ ´

}“´}.

To find the negative of only one part of a complex number in the X-register:

∙Press “to negate the real part only.

∙Press ´ } “ ´ } to negate the imaginary part only, forming the complex conjugate.

Clearing a Complex Number

Inevitably you will need to clear a complex number. You can clear only one part at a time, but you can then write over both parts (since −and ` disable the stack).

Clearing the Real X-Register.Pressing − (or `) with the calculator in Complex mode clears only the number in the real X-register; it does not clear the number in the imaginary X-register.

Example: Change 6 + 8i to 7 + 8i and subtract it from the previous entry. (Use ´}or ´%to view the imaginary part in X.) Assume a, b, c and d represent parts of complex numbers.

	Re	Im		Re	Im	Re	Im		Re	Im
T	a	b		a	b	a	b		a	b
Z	c	d		c	d	c	d		a	b
Y	6	0		6	0	6	0		c	d
X	6	8		0	8	7	8		-1	-8
Keys:
			−		7			- (or other

operation)

Since clearing disables the stack (as explained above), the next number you enter will replace the cleared value. If you want to replace the real part with zero, after clearing use v or any other function to terminate digit entry (otherwise the next number you enter will write over the zero); the imaginary part will remain unchanged. You can then continue with any calculator function.