# Why is $\int_{\pi/2}^0 \cos x dx$ negative? [closed]

$$\int_{\pi/2}^0 \cos x dx = -1$$

But we know that integration is an area under the curve.

$$\cos x$$ is positive between $$0$$ and $$\pi/2$$. So, the area should be positive. But why is the integration negative?

$$\int_{\frac\pi2}^0\cos (x)\mathrm dx=-\int_0^{\frac\pi2}\cos (x)\mathrm dx=-1.$$