asinh() acosh() atanh() provide wrong value in case angleMeasurementMode is set to degree.

[KamranKhan-DL]

For anyone facing the same issue, following is the solution.

+ (DDMathFunction) asinhFunction {
    DDMathFunction function = ^ DDExpression* (NSArray *arguments, NSDictionary *variables, DDMathEvaluator *evaluator, NSError **error) {
        REQUIRE_N_ARGS(1);
        DDExpression *argument = [arguments objectAtIndex:0];
        argument = _DDDTOR(argument, evaluator, error);
        NSNumber *n = [[arguments objectAtIndex:0] evaluateWithSubstitutions:variables evaluator:evaluator error:error];
        RETURN_IF_NIL(n);

        NSNumber *result = [NSNumber numberWithDouble:asinh([n doubleValue])];
        return [DDExpression numberExpressionWithNumber:result];
    };
    return DD_AUTORELEASE([function copy]);
}

+ (DDMathFunction) acoshFunction {
    DDMathFunction function = ^ DDExpression* (NSArray *arguments, NSDictionary *variables, DDMathEvaluator *evaluator, NSError **error) {
        REQUIRE_N_ARGS(1);
        DDExpression *argument = [arguments objectAtIndex:0];
        argument = _DDDTOR(argument, evaluator, error);
        NSNumber *n = [[arguments objectAtIndex:0] evaluateWithSubstitutions:variables evaluator:evaluator error:error];
        RETURN_IF_NIL(n);

        NSNumber *result = [NSNumber numberWithDouble:acosh([n doubleValue])];
        return [DDExpression numberExpressionWithNumber:result];
    };
    return DD_AUTORELEASE([function copy]);
}

+ (DDMathFunction) atanhFunction {
    DDMathFunction function = ^ DDExpression* (NSArray *arguments, NSDictionary *variables, DDMathEvaluator *evaluator, NSError **error) {
        REQUIRE_N_ARGS(1);
        DDExpression *argument = [arguments objectAtIndex:0];
        argument = _DDDTOR(argument, evaluator, error);
        NSNumber *n = [[arguments objectAtIndex:0] evaluateWithSubstitutions:variables evaluator:evaluator error:error];
        RETURN_IF_NIL(n);

        NSNumber *result = [NSNumber numberWithDouble:atanh([n doubleValue])];
        return [DDExpression numberExpressionWithNumber:result];
    };
    return DD_AUTORELEASE([function copy]);
}

[davedelong]

This is fixed on the 2.0 branch, which will be merged in to master soon.