Adding shortcode to a slider

Yes you can do it, adding this to your child-theme functions.php:

add_filter('tc_slide_text_length', 'my_tc_slide_text_length');
function my_tc_slide_text_length(){
    return 500; /*change this value to suit your needs*/
}
add_filter('tc_slider_display', 'do_my_shortcode');
function do_my_shortcode($html){
    return do_shortcode(html_entity_decode($html));
}

Hope this helps.

wow thanks d4z

but where in functions php do i insert the code?

Do you have a child theme?
https://www.themesandco.com/customizr/how-to-customize-customizr-wordpress-theme/