Find All Real Solutions

**fdrhs1984** · August 13th 2010, 04:27 AM

Find all real sollutions of the equation exactly.y^4 - 7y^2 + 6 = 0

**Ackbeet** · August 13th 2010, 04:59 AM

To solve this problem, you should use a dirty trick: "see" this problem as a quadratic in some variable. Do you follow me?

**fdrhs1984** · August 13th 2010, 06:19 AM

Originally Posted by Ackbeet

To solve this problem, you should use a dirty trick: "see" this problem as a quadratic in some variable. Do you follow me?

I don't know what you mean. Can you show me what to do? Can you show me the steps?

**Prove It** · August 13th 2010, 06:22 AM

Let $y^2 = Y$ .

What happens to the equation?

**fdrhs1984** · August 13th 2010, 06:31 AM

Originally Posted by Prove It

Let $y^2 = Y$ .

What happens to the equation?

The equation becomes quadratic, right?

**Prove It** · August 13th 2010, 06:44 AM

Correct.

What quadratic do you get? Remember that $y^4 = (y^2)^2$ .

Thread: Find All Real Solutions