Rmarkdown slidy increase size of equation

Question

I am using a slidy presentation with Rmarkdown. The output is html (not pdf). I have a math equation like:

$$\eta_i = \widetilde{r_i} - \widehat{r_i}$$ 

I would like to increase the size of this equation only within the slide, not the whole slide.

Is this possible?

Answer 1

I did $$\large \eta_i = \widetilde{r_i} - \widehat{r_i}$$

or

$$\huge \eta_i = \widetilde{r_i} - \widehat{r_i}$$

and it worked