Question

plz help ne solving these problems​

Answer 1

ans 26.  cos45°/sec30°+cosec30°

$\frac{1/\sqrt{2}}{1/2+2}$

$\frac{1/\sqrt{2} }{5/2}$

$\frac{2}{5\sqrt{2} }$

$\frac{\sqrt{2} }{5}$

ans 22. let 3+√5 is rational

so, it can be written in the form of a/b where a and b integers and b≠0

therefore, 3+√5= a/b

                     √5= a/b -3

as a/b -3 is rational it means  √5 is also rational

but it contradicts the fact that  √5 is irrational and this contradiction has arisen due to our wrong assumption that 3+√5 is  rational

therefore, 3+ √5 is irrational

hence proved

hope it helps ...    :)