brainteaser: change a value by 90 (but answer must lie between 0-180 )

[Chris.Holland16]

Please see below ( I want to do step 3 - change a value by 90 degrees)
but the answer has to be between 0 and 180

e.g. 45 becomes 90

e.g. 95 becomes 185 (but this is wrong, so SUBTRACT 90 instead) anwer
is 5



************************************************************************************
from http://www.usaeyes.org/faq/subjects/script.htm

Minus Cylinder or Plus Cylinder

Spectacle prescriptions can be written in two value sets, minus
cylinder or plus cylinder, which are mutually exclusive of each other
but provide the same information. As a rule, ophthalmologists write
scripts in minus cylinder whereas optometrists write scripts in plus
cylinder. Why these two professions cannot get together and decide on a
common method of reporting refractive error is impossible to explain,
but if you have ever had competing siblings in your family, you may get
an idea why this has not yet occurred.

To convert a minus cylinder form prescription into plus cylinder, or to
convert the plus cylinder form into minus cylinder, do the following:

1) Add the sphere and cylinder powers together; this becomes the new
sphere power.
2) Change the sign of the cylinder power, from minus (-) to plus (+)
or from plus (+) to minus (-).
3) Change the axis value by 90°, remembering that the axis must be a
number from 1 to 180.
The following lens prescriptions, therefore, are equivalent and
interchangeable

************************************************************************************

 

[Stephan Bielicke]

Hello,

Please see below ( I want to do step 3 - change a value by 90 degrees)
but the answer has to be between 0 and 180

e.g. 45 becomes 90

? 135 ?

e.g. 95 becomes 185 (but this is wrong, so SUBTRACT 90 instead) anwer is 5

try
=MOD(A1+90;180)
if a1 contains the original value.

HTH
Stefan

 

[Ron Rosenfeld]

Please see below ( I want to do step 3 - change a value by 90 degrees)
but the answer has to be between 0 and 180

e.g. 45 becomes 90

e.g. 95 becomes 185 (but this is wrong, so SUBTRACT 90 instead) anwer
is 5


=MOD(A1+90,180)+(MOD(A1+90,180)=0)*180






************************************************************************************
from http://www.usaeyes.org/faq/subjects/script.htm

Minus Cylinder or Plus Cylinder

Spectacle prescriptions can be written in two value sets, minus
cylinder or plus cylinder, which are mutually exclusive of each other
but provide the same information. As a rule, ophthalmologists write
scripts in minus cylinder whereas optometrists write scripts in plus
cylinder. Why these two professions cannot get together and decide on a
common method of reporting refractive error is impossible to explain,
but if you have ever had competing siblings in your family, you may get
an idea why this has not yet occurred.

To convert a minus cylinder form prescription into plus cylinder, or to
convert the plus cylinder form into minus cylinder, do the following:

1) Add the sphere and cylinder powers together; this becomes the new
sphere power.
2) Change the sign of the cylinder power, from minus (-) to plus (+)
or from plus (+) to minus (-).
3) Change the axis value by 90°, remembering that the axis must be a
number from 1 to 180.
The following lens prescriptions, therefore, are equivalent and
interchangeable

************************************************************************************

--ron

 

[Guest]

=mod(a1+90,180) will constrain the sum of a1 and 90 to the range of 0-180.

 

[Ron Rosenfeld]

=mod(a1+90,180) will constrain the sum of a1 and 90 to the range of 0-180.

Actually it will constrain it to the range of 0-179.




--ron

 

[Chris.Holland16]

=mod(a1+90,180) will constrain the sum of a1 and 90 to the range of 0-180.

Thanks you - that's excellent.

but how do i contrain sum from 1 to 180 (not 0 to 180)

(so 90 degrees becomes 180 instead of 0)

 

[Chris.Holland16]

Hello,



? 135 ?


try
=MOD(A1+90;180)
if a1 contains the original value.

HTH
Stefan

thanks for correcting my maths!

=MOD(A1+90;180) didn't work - I replaced the semicolon ( ; ) with a
comma ( , ) - you probably meant this

 

[Chris.Holland16]

=MOD(A1+90,180)+(MOD(A1+90,180)=0)*180

Ron,


PERFECT

I have just realised that your answer is perfect

 

[Chris.Holland16]

Thanks you - that's excellent.

but how do i contrain sum from 1 to 180 (not 0 to 180)

(so 90 degrees becomes 180 instead of 0)

Sorry - ignore this comment . Ron did it correctly:
=MOD(A1+90,180)+(MOD(A1+90,180)=0)*180

Ron if you have time, please can you explain your formula (if possible)

 

[Ron Rosenfeld]

Sorry - ignore this comment . Ron did it correctly:
=MOD(A1+90,180)+(MOD(A1+90,180)=0)*180

Ron if you have time, please can you explain your formula (if possible)

I just made '0' a special case.

The first part of the function:

=MOD(A1+90,180)

constrains the results to 0-179.

By changing the '0' to '180', we constrain the results to 1-180.

The function (MOD(A1+90,180)=0) will evaluate to TRUE or FALSE. In
Excelspeak, TRUE = 1 and FALSE =0. So if the function evaluates to '0', we
then have:

=0 + TRUE * 180
=0 + 1*180
=180.

If the first part evaluates to anything other than 0,then the second part
evaluates to 0*180 = 0 so it is ignored.

It's really the same as writing:

=MOD(A1+90,180) + IF(MOD(A1+90,180)=0,180,0)


--ron

 

[Ron Rosenfeld]

Ron,


PERFECT

I have just realised that your answer is perfect

Thank you for the feedback. Glad to help.
--ron