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# If Statment with

## If Statment with

(OP)
Hi

I am new to Mathcad and a bit confused. I am trying to use an if statement to say something like the following:

#### CODE

Lr(R,gamma,theta):=if(phi(R,gamma,theta)< theta, 2, 10)

where

#### CODE

phi(R,gamma,theta):= atan(hr/Lg(theta))
Lg(theta):= Ls(theta)*cos(theta)
Ls(theta):= 2*hr/sin(theta)

However it wont work when i try to output the value of

#### CODE

Lr(R,gamma,theta)=
, I am getting a "must be real" error. If i change the boolean statement in the if statement to

#### CODE

phi(R,gamma,theta)= theta
it outputs an answer fine, however this is not what i need to work out! Does anyone know why this is?

### RE: If Statment with

What values or R, gamma, theta are you using?

TTFN

### RE: If Statment with

(OP)
I'm not sure what I've done but it seems to work now! The values of R, gamma and theta vary but in my examples that didnt work R was about 15, gamma was 90 and theta about 0.2. I've been playing around a bit with the algorithms and think I may have been using a variable in the right-hand part of the declaration that I hadn't put as an arguement in the left-hand part, but as this variable was declared at some point above this then it wasn't being picked up as not declared. It may have had an inappropriate value in from another calulation which was causing this. I am not sure though.

### RE: If Statment with

Bear in mind that the default unit for trig functions in Mathcad is the radian, not degree.

TTFN

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