Using the Chain Rule when differentiating

I have a question: find $\frac{dy}{dx}$ for $y = (2x^4 + 1)^6$.

The final answer I get for this is $48x^3(2x^4+1)^5$.

However, the solutions say that the answer should be $48x^3(2x^4+1)^6$.

Where did the power of 6 come from ? is this a mistake in the solutions or have I done something incorrect ?

• Are you sure the original problem is written correctly? Your answer is correct for the stated problem. – Moo Dec 14 '16 at 16:19
• Yes it is written correctly and yh i thought so. Thanks :) – Dan Dec 14 '16 at 16:21

$$\frac{dy}{dx}=6\cdot(2x^4+1)^5\frac{d}{dx}(2x^4+1)=48\cdot x^3\cdot (2x^4+1)^5$$