Here's the question you clicked on:
lilg132
intergrate want to check if the answer is right
\[\int\limits_{}^{}6.6\sin(3x) - 2.5\cos(0.5x)dx\]
answer ? \[{-6.6 \over 3}\cos(3x) + {2.5 \over 0.5} \sin(0.5x) + c\]
Looks good to me. You can always take the derivative of your answer and see if you get the expression inside the integral for problems like this, though. :)
because when i typed it in wolframalpa it gave me a completely different answer https://www.wolframalpha.com/input/?i=integrate+6.6sin%283x%29+-+2.5cos%280.5x%29dx