Question

If a sinx=7 then sec (90-x) is
equal to :
A.
9/232
.
B. 7/9
C. 9/7
D. None​

Answer 1

Step-by-step explanation:

2sinx+15cos

2

x=7

2sinx+15(1−sin

2

x)−7=0

2sinx−15sin

2

x+8=0

15sin

2

x−2sinx−8=0

sinx=

2.15

2±

4+4.15.8

=

30

2±

4+480

=

30

2±22

=

30

24

,

30

−20

sinx>0 (∵0<x<90

o

)

sinx=

30

24

=

5

4

cosx=

1−

25

16

=

25

9

=

5

3

tanx=

cosx

sinx

=

3/5

4/5

=

3

4

∴tanx=

3

4

.