Diketahui tan x = 1/2, maka 2 sin (phi/2 + x) + cos (180-x) =.... Question from @kettyputri

ImmanuelSinaga $$\begin{align}2~Sin(90+x)+Cos~(180-x) &=2~Cos~x-Cos~x \\ &= Cos~x \\ \text{Ingat :} \\ \boxed{1+tan^2\alpha=sec^2\x} \\ &=1+\frac{1}{4}=sec^2x \\ &=sec~x=\underline{+}~\frac{\sqrt{5}}{2} \\ &=Cos~x=\underline{+}\frac{2}{\sqrt{5}} \ \text{atau} \ \underline{+}~\frac{2}{5}\sqrt{5} \\ 2~Sin(90+x)+Cos~(180-x) &=\underline{+}~\frac{2}{5}\sqrt{5} \end{align} \\$

izharulhaq78 $tanx= \frac{1}{2} \\ \frac{sinx}{cosx}= \frac{1}{2} \\ 2sinx=cosx \\ \\ 2sin(\frac{\pi}{2}+x)+cos(180-x) \\ 2(sin\frac{\pi}{2}cosx+cos\frac{\pi}{2}sinx)+(cos180cosx+sin180sinx) \\2(1\times cosx+0\times sinx)+(-1\times cosx+0\times sinx) \\ 2(cosx+0)+(- cosx+0) \\ 2(cosx)+(- cosx) \\ 2cosx-cosx \\ cosx \\ 2sinx \\ 2\times \frac{1}{ \sqrt{5} } \\ \frac{2}{ \sqrt{5} } \\ \frac{2}{\sqrt{5}}\times \frac{\sqrt{5}}{\sqrt{5}} \\ \frac{2\sqrt{5}}{5}$

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ImmanuelSinaga dari mana 1/(akar 5)

izharulhaq78 Phytagoras

ImmanuelSinaga owh, kok gk d jelaskan ^_^

izharulhaq78 Awalnya sih pengen dikasih penjelasannya, cuma bingung mau taruh di mana

ImmanuelSinaga owh, (y) brainly elite

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