Average speed=Total Distance Covered\<span>Total time take<span>n
T.D=240+180=420
T.T=2.5+2=4.5
420\4.5=93.3 km\h
answer=D</span></span>
it is b -30 plz give me brainlist
Answer: option a.
Step-by-step explanation:
By definition, we know that:
![cos^2(\theta)=1-sen^2(\theta)\\\\tan(\theta)=\frac{sin(\theta)}{cos(\theta)}](https://tex.z-dn.net/?f=cos%5E2%28%5Ctheta%29%3D1-sen%5E2%28%5Ctheta%29%5C%5C%5C%5Ctan%28%5Ctheta%29%3D%5Cfrac%7Bsin%28%5Ctheta%29%7D%7Bcos%28%5Ctheta%29%7D)
Substitute
into the first equation, solve for the cosine and simplify. Then, you obtain:
![cos(\theta)=\±\sqrt{1-(\frac{6}{11})^2}\\\\cos(\theta)=\±\sqrt{\frac{85}{121}}\\\\ cos(\theta)=\±\frac{\sqrt{85}}{11}](https://tex.z-dn.net/?f=cos%28%5Ctheta%29%3D%5C%C2%B1%5Csqrt%7B1-%28%5Cfrac%7B6%7D%7B11%7D%29%5E2%7D%5C%5C%5C%5Ccos%28%5Ctheta%29%3D%5C%C2%B1%5Csqrt%7B%5Cfrac%7B85%7D%7B121%7D%7D%5C%5C%5C%5C%20cos%28%5Ctheta%29%3D%5C%C2%B1%5Cfrac%7B%5Csqrt%7B85%7D%7D%7B11%7D)
As
then
:
![cos(\theta)=-\frac{\sqrt{85}}{11}](https://tex.z-dn.net/?f=cos%28%5Ctheta%29%3D-%5Cfrac%7B%5Csqrt%7B85%7D%7D%7B11%7D)
Now we can find
:
![tan\theta=\frac{\frac{6}{11}}{-\frac{\sqrt{85}}{11}}\\\\tan\theta=-\frac{6\sqrt{85}}{85}](https://tex.z-dn.net/?f=tan%5Ctheta%3D%5Cfrac%7B%5Cfrac%7B6%7D%7B11%7D%7D%7B-%5Cfrac%7B%5Csqrt%7B85%7D%7D%7B11%7D%7D%5C%5C%5C%5Ctan%5Ctheta%3D-%5Cfrac%7B6%5Csqrt%7B85%7D%7D%7B85%7D)