Question

The value of the definite integral / 212x – sin(x) dx / 122x-sin(x) is

Answer 1

Hi there!

$\boxed{= 70 + cos(12) - cos(2) \approx 71.26}$

$\int\limits^{12}_{2} {x-sin(x)} \, dx$

We can evaluate using the power rule and trig rules:

$\int x^n = \frac{x^{n+1}}{n+1}$

$\int x = \frac{1}{2}x^{2}$

$\int -sin(x) = cos(x)$

Therefore:

$\int\limits^{12}_{2} {x-sin(x)} \, dx = [\frac{1}{2}x^{2}+cos(x)]_{2}^{12}$

Evaluate:

$(\frac{1}{2}(12^{2})+cos(12)) - (\frac{1}{2}(2^2)+cos(2))\\= (72 + cos(12)) - (2 + cos(2))\\\\= 70 + cos(12) - cos(2) \approx 71.26$