Question

7. If sin x + cos x = 1, then the value of sin 2x =
a 1
b 1÷z
c 0
d -1
​

Answer 1

Step-by-step explanation:

sinx+cosx=1

squaring both side

we get

sin²x+cos²x+2sinxcosx=1

2sinxcosx+1=1 because sin²x+cos ²x=1

2sinxcosx=0

from trignometeric identity

sin2x=2sinxcosx

that means sin2x=0

Answer 2

C is the right answer
See figures attached