code for above diagrams

> plot(sqrt(1-x^2),x=-1..1, title= `Graph of y = sqrt(1-x^2)`, titlefont=[TIMES,BOLD,18],scaling=constrained, xtickmarks = [-1,0,1], ytickmarks=[-1,0,1],labelfont=[TIMES,BOLD,18], view =[-1.1..1.1,-1.1..1.1],axesfont=[TIMES,BOLD,14]);

> plot(-sqrt(1-x^2),x=-1..1, title=`Graph of y=-sqrt(1-x^2)`, titlefont=[TIMES,BOLD,18],scaling=constrained, xtickmarks = [-1,0,1], ytickmarks=[-1,0,1],labelfont=[TIMES,BOLD,18], view =[-1.1..1.1,-1.1.. .1],axesfont=[TIMES,BOLD,14]);