HP 48gII hp 48gII_user's manual_English_E_HDPMSG48E67_V2.pdf - Page 235

Chapter 7 Solving multiple equations Many problems of science and engineering require the simultaneous solutions of more than one equation. The calculator provides several procedures for solving multiple equations as presented below. Please notice that no discussion of solving systems of linear equations is presented in this chapter. Linear systems solutions will be discussed in detail in subsequent chapters on matrices and linear algebra. Rational equation systems Equations that can be re-written as polynomials or rational algebraic expressions can be solved directly by the calculator by using the function SOLVE. You need to provide the list of equations as elements of a vector. The list of variables to solve for must also be provided as a vector. Make sure that the CAS is set to mode Exact before attempting a solution using this procedure. Also, the more complicated the expressions, the longer the CAS takes in solving a particular system of equations. Examples of this application follow: Example 1 - Projectile motion Use function SOLVE with the following vector arguments, the first being the list of equations: ['x = x0 + v0*COS(θ0)*t' 'y =y0+v0*SIN(θ0)*t - g*t^2/2']`, and the second being the variables to solve for, say t and y0, i.e., ['t' 'y0']. The solution in this case will be provided using the RPN mode. The only reason being that we can build the solution step by step. The solution in the ALG mode is very similar. First, we store the first vector (equations) into variable A2, and the vector of variables into variable A1. The following screen shows the RPN stack before saving the variables. Page 7-1