4. State whether the following are true or false. Justify your answer
6) sin (A+B)= sin A+ sin B.
6) The value of sin0 increases as increases,
() The value of cos 0 increases as increases.
(iv) sin 8 = cos 0 for all values of 0.
(V) cot A is not defined for A=0
Answers
Answered by
0
Answer:
(i) False
sin(A+B)=sinA+sinB
A=45
o
,B=45
o
LHS: sin(45
o
+45
o
)=sin90
o
=1
RHS : sinA+sinB=
2
1
+
2
1
=
2
2
=
2
LHS
=RHS
(ii) True
sin0
o
=0sin30
o
=
2
1
=sin45
o
=
2
1
,sin60
o
=
2
3
sin90
o
=1
∴θ increase ans value of sinθ also increase.
(iii) False
cos0=1,cos30=
2
13
,cos45=
2
1
cos60=
2
1
,cos90=0
Value of cosθ does not increase from 0<0<90
o
(iv) False
This is true for θ=45
o
Let θ=90
o
sin90=1,cos90=0
(v) True
cotA=
sinA
cosA
cot0
o
=
sin0
cos0
=
0
1
=not defined
Similar questions