`Graph` Crashes when frequency not separated from x with '*'

[nichyjt]

Description

When testing the program's Graph function, when the command Graph 1*sin(2x) is given, the application crashes.

Reproduction

Type in the command Graph 1*[trig]([number]x)

Any permutation of this will result in a crash. Some ested inputs:

• `Graph 1*sin(2x)
• Graph 1*tan(2x)
• Graph 5*tan(5x - 10)

Screenshots

1*sin(2x)

10*tan(5x+20)

[nus-pe-bot]

Your response not required for this bug as the team has accepted the bug as it is.