Question

sinA+cosA=1 prove that.

Answer 1

sinA+CosA=1(given)--1 
Sq both sides 
(sinA+cosA)^2= 
sin^2A+cos^2+2sinAcosA=1 
1+2sinAcosA=1 
2sinAcosA=0 
sinAcosA=0 
sinA=0 
Now substituting sinA's value 
0+cosA=1 
cosA=1 
Case 1 
sinA=0 
cosA=1 
Let an equation sinA-cosA 
0-1=-1 
sinA-cosA=-1 
Now taking the same equation 
sinAcosA=0 
cosA=0 and thus by substituting in 1 we get sinA=1 
Case 2 
sinA=1 
cosA=0 
Let us take equation sinA-cosA 
1-0=1 
sinA-cosA=1 

Answer 2

take triangle ABC right angled at b
from u will get it try to find value of sin a than cos a
add it and u will get the anwser