Melody

It is written as an imaginary number already.

i is the basis of the whole imaginary number system.     i=sqrt(-1)

I suggest that you study these examples

$$\\-8+\frac{3}{4}*3\\\\
-8+\frac{9}{4}\\\\
-8+2+\frac{1}{4}\\\\
-6+\frac{1}{4}\\\\
-5\frac{3}{4}\\\\$$

the button that you are describing anon looks like this

$${{\mathtt{x}}}^{{\mathtt{y}}}$$

$$3\times 10\;\; [x^y] \;\;8\;=\\\\$$

on the web2 calc you can just type in  

3*10^8                           (Just like mathematician said)  

$$\\f(x) = \frac{x^2}{5} + 2x\\\\
f'(x) = \frac{2x}{5} + 2\\\\
f"(x) = \frac{2}{5}\\\\$$

41=16/3% of X

$$\\41=\frac{16}{3}\div 100 \;\; * \;\; X\\\\
41=\frac{16}{3}\times \frac{1}{100} \;\; * \;\; X\\\\
41=\frac{16}{300} \;\; * \;\; X\\\\
41\times\frac{300}{16} =\frac{16}{300}\times\frac{300}{16} \;\; * \;\; X\\\\
41\times\frac{300}{16} =\; X\\\\
X=41\times\frac{300}{16} \\\\$$

$${\mathtt{41}}{\mathtt{\,\times\,}}\left({\frac{{\mathtt{300}}}{{\mathtt{16}}}}\right) = {\frac{{\mathtt{3\,075}}}{{\mathtt{4}}}} = {\mathtt{768.75}}$$

That is what inverse sin or arcsin is for

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}^{\!\!\mathtt{-1}}{\left({\mathtt{0.866\: \!025\: \!403\: \!784}}\right)} = {\mathtt{59.999\: \!999\: \!999\: \!95^{\circ}}}$$

$$Y(Y)^5=Y^1*Y^5=Y^{1+5}=Y^6$$

$$\\\frac{x+3}{10}=\frac{2}{5}\\\\
10\times\frac{x+3}{10}=10\times\frac{2}{5}\\\\
x+3=2\times\frac{2}{1}\\\\
x+3=4\\\\
x=1$$

OR

$$\\x+\frac{3}{10}=\frac{2}{5}\\\\
x+0.3=0.4\\
x=0.4-0.3\\
x=0.1\\$$

$$\\.5=(.85)^t\\\\
log(0.5)=log(0.85)^t\\\\
log(0.5)=t*log(0.85)\\\\
t=\frac{log(0.5)}{log(0.85)}\\\\$$

$${\frac{{log}_{10}\left({\mathtt{0.5}}\right)}{{log}_{10}\left({\mathtt{0.85}}\right)}} = {\mathtt{4.265\: \!024\: \!281\: \!798\: \!725\: \!7}}$$