MATLAB by rudra pratap

2.8 Lesson 8: Symbolic Computation
49
Define a column vector v = [X yf.
Find the inner product vTv. Note
that MATLAB assumes x and y to
be complex (default data type)
x*conj (x) +
variables and hence
VT 7! = XX + yf} .
>> ·
>> inner
inner _product
XA2 + yA2
be real and evaluate the inner
product.
Since x and y are real,
v T v = x2 + y2 .
>> syms a b
>> expl 1a*x + b *y - 3 I ;
>> exp2 I -x
+ 2*a*y -5 I ;
>> [x, y]
= solve (expl , exp2 )
Solve two simultaneous algebraic
equations for x and y:
ax +by - 3 0
-x + 2ay - 5 0
X =
(6*a - 5*b) / (2* aA2 + b)
y =
(5*a + 3) / (2*aA2 + b)
>> sub s(exp l)
ans =
Substitute the values of x and y just
found in expl to check the result.
( b* (S*a + 3) )/(2*a A 2 + b) + ( a* (6*a - 5*b) ) / (2*aA2 + b) -3
>> s i mp lify (ans)
ans
0
Simplify the answer to see if it
reduces to zero (as it must in order
to satisfy the equation).
>> pretty (subs ( exp2 ))
2 a (5 a + 3) 6 a - 5 b
Use pretty to get the expression in
more readable form.
------------- - --------- - 5
2
2 a + b 2 · a
Figure 2.11: LesRon 8: Symbolic calculations.