Help. i dont know how a log works here Find the derivative of the function. y = 8^( 8 − x ^2)?

　
y = 8^(8−x²)
ln y = ln(8^(8−x²))
ln y = (8−x²) ln(8)

Differentiate both sides:
1/y dy/dx = −2x ln(8)
dy/dx = −2x ln(8) y
dy/dx = −2x ln(8) 8^(8−x²)