how $2x=x$ , related to differential calculus

Question

can anybody please tell me what's happening here ?

$$1^2=1$$

$$2^2=2+2$$

$$3^2=3+3+3$$

$$x^2 = x+x+\cdots+x \mbox{ ($x$ times)}$$

differentiating both the sides $$2x = 1 + 1 + \cdots+1 \mbox{ ($x$ times)}$$

thank u

Answer 1

When you are getting $$x^2 = x+x+\cdots+x \mbox{ ($x$ times)}$$ then $x$ is a constant no not a variable. So, differentiating both side you will get $0=0$ which is true.