1. **State the problem:** Given the quadratic equation $$x^2 - 3ax + a^2 = 0$$ with roots $$\alpha$$ and $$\beta$$, and the condition $$\alpha^2 + \beta^2 = \frac{7}{9}$$, find the value of $$a$$.
2. **Recall the relationships between roots and coefficients:** For a quadratic equation $$x^2 + bx + c = 0$$ with roots $$\alpha$$ and $$\beta$$,
- Sum of roots: $$\alpha + \beta = -b$$
- Product of roots: $$\alpha \beta = c$$
3. **Apply these to our equation:** Here, the equation is $$x^2 - 3ax + a^2 = 0$$, so
- $$\alpha + \beta = 3a$$
- $$\alpha \beta = a^2$$
4. **Use the identity for sum of squares of roots:**
$$\alpha^2 + \beta^2 = (\alpha + \beta)^2 - 2\alpha\beta$$
Substitute the known values:
$$\alpha^2 + \beta^2 = (3a)^2 - 2a^2 = 9a^2 - 2a^2 = 7a^2$$
5. **Set equal to given value and solve for $$a$$:**
$$7a^2 = \frac{7}{9}$$
Divide both sides by 7:
$$a^2 = \frac{1}{9}$$
Take square root:
$$a = \pm \frac{1}{3}$$
6. **Final answer:**
$$a = \frac{1}{3} \text{ or } a = -\frac{1}{3}$$
Roots Value
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.